SOLUTION: Please help me solve this problems :
1. On Dave's birthday, his brother Harry is 17 yrs younger than 3 times his age. The boy's father , Tom is 12 yrs. older than twice Harry's a
Algebra.Com
Question 153913: Please help me solve this problems :
1. On Dave's birthday, his brother Harry is 17 yrs younger than 3 times his age. The boy's father , Tom is 12 yrs. older than twice Harry's age. If Dave is 7 years younger than his brother , how many candles are on Dave's cake?
2. When Alvin divides each of 5 consecutive integers by his age, the sum of the 5 remainders he gets is 32. When Susan , several yrs. older, divides each of a different set of 5 consecutive integers by her age, the sum of the five remainders she gets is also 32. What is the sum of the ages of Alvin and Susan?
Found 2 solutions by josmiceli, Edwin McCravy:
Answer by josmiceli(19441) (Show Source): You can put this solution on YOUR website!
= Dave's age now
= Harry's age now
= Tom's age now
(1)
(2)
(3)
--------------------
Replace in (1) with in (3)
(1)
Subtract from both sides
-------------------
(3)
There are 12 candles on Dave's cake
Note that I didn't need to know the father's age to solve this
-------------------
The 2nd one may be too tough for me
Answer by Edwin McCravy(20056) (Show Source): You can put this solution on YOUR website!
Edwin's complete solution:
Please help me solve this problems :
1. On Dave's birthday, his brother Harry is 17 yrs younger than 3 times his age. The boy's father , Tom is 12 yrs. older than twice Harry's age. If Dave is 7 years younger than his brother , how many candles are on Dave's cake?
Please help me solve this problems :
>>...his brother Harry is 17 yrs younger than 3 times his age...<<
H = 3D - 17
>>...The boy's father , Tom is 12 yrs. older than twice Harry's age...<<
T = 2H + 12
>>...Dave is 7 years younger than his brother...<<
D = H - 7
-3D + H = -17
- 2H + T = 12
D - H = -7
Solve that and get D=12, H=19, T=50
----------------------
2. When Alvin divides each of 5 consecutive integers by his age, the sum of the 5 remainders he gets is 32. When Susan , several yrs. older, divides each of a different set of 5 consecutive integers by her age, the sum of the five remainders she gets is also 32. What is the sum of the ages of Alvin and Susan?
Let either one of their ages be A.
Let the 5 consecutive integers be I1,I2,I3,I4,I5
Let the remainders when these integers are divided
by A be R1,R2,R3,R4,R5
If none of the consecutive integers is A or
or a multiple of A, then the 5 remainders will
themselves be 5 consecutive integers.
Let's see if there exist 5 consecutive integers
which the remainders could be, so as to have the sum 32.
No, that is not possible, for n doesn't come out
to an integer.
That means one of 5 consectutive integers must
be a multiple of A, say kA
Whichever one of the 5 is kA, The remainder left when
dividing by A will of course be 0.
Any of the 5 remainders of members of the 5 that are
less than kA, will be consecutive integers, the largest
of which must be A-1, then the one below that will be
A-2, and so on.
Any of the 5 remainders that are greater than the multiple
of A will be consecutive integers 1,2,3, and so on
Then we have 5 cases to consider, that is, when kA comes
1st, 2nd, 3rd, 4th, and 5th.
I1 I2 I3 I4 I5 R1 R2 R3 R4 R5 Sum
case 1. kA kA+1 kA+2 kA+3 kA+4 0 1 2 3 4 10
case 2. kA-1 kA kA+1 kA+2 kA+3 A-1 0 1 2 3 A+5
case 3. kA-2 kA-1 kA kA+1 kA+2 A-2 A-1 0 1 2 2A
case 4. kA-3 kA-2 kA-1 kA kA+1 A-3 A-2 A-1 0 1 3A-5
case 5. kA-4 kA-3 kA-2 kA-1 kA A-4 A-3 A-2 A-1 0 4A-10
We set each of those sums on the far right equal to 32 and see which,
if any, have an integer solution:
Case 1. This is out because 10 does not equal 32.
Case 2. A+5 = 32
A = 27
That's a whole number, so one of their ages can be 27.
Case 3. 2A = 32
A = 16
That's a whole number, so one of their ages can be 16.
Case 4. 3A-5 = 32
2A = 37
A = 27/2
That is not a whole number, so Case 4 is out.
Case 5. 4A-10= 32
4A = 42
A = 21/2
That is not a whole number, so Case 5 is out.
So Alvin is 16 and Susan is 27, making the sum of their ages 43.
Now there is no way to tell whether Susan's 5 consecutive
integers were
26,27,28,29,30, or 53,54,55,56,57, or 80,81,82,83,84 or etc.
There is also no way to tell whether Alvin's 5 consecutive
integers were
14,15,16,17,18, or 30,31,32,33,34, or 46,47,48,49,50 or etc.
However he must be 16 and she must be 27.
Edwin
RELATED QUESTIONS
On Dave's birthday, his brother Harry is 17 years younger than 3 times his age. The... (answered by ankor@dixie-net.com)
Please solve this question
Taz is 5 years older than his brother and 1 year younger than (answered by Edwin McCravy)
Please solve this question
Taz is 5 years older than his brother and 1 year younger than (answered by ankor@dixie-net.com,MathTherapy)
harry is x years old, his brother is two times older and his sister is 5 years younger... (answered by ankor@dixie-net.com)
please help me with this age problem;
Harry is one year older than twice his... (answered by stanbon)
PLS. HELP ME WITH THIS problemS. ASAP
~peter's age 13 yrs. ago of his age was 1/3 of... (answered by ankor@dixie-net.com)
please help me with these problems:
1. Olan is 3 years older than his sister, Rose.... (answered by ankor@dixie-net.com)
joe is 15 yrs younger then his brother. five years from now, three times his own age will (answered by db12345)
Please help with this. Thanks
Eric is 2 years younger than his brother Bill and 2... (answered by ankor@dixie-net.com,gonzo)