SOLUTION: Five times sally's age now exceeds 3 times John's age by 30. In 10 years, twice sally's age will exceed john's age by 26. What will be their ages 13 years from now?
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Question 66860This question is from textbook Advanced mathematics
: Five times sally's age now exceeds 3 times John's age by 30. In 10 years, twice sally's age will exceed john's age by 26. What will be their ages 13 years from now? This question is from textbook Advanced mathematics
You can put this solution on YOUR website! Let s = sally's age now; j = john's age now
:
Write an equation for each statement. just like it says:
"Five times sally's age now exceeds 3 times John's age by 30."
5*s = (3*j) + 30
or
5s = 3j + 30
:
"In 10 years, twice sally's age will exceed john's age by 26."
:
Their ages in 10 years would be (s+10) and (j+10), right?
:
A simple equation from this statement:
2(s+10) = (j+10) + 26
2s + 20 = j + 36
2s + 20 - 36 = j
2s - 16 = j
Or
j = (2s - 16)
:
Remember our 1st equation; 5s = 3j + 30. Substitute (2s-16) for j, find s
5s = 3(2s-16) + 30
5s = 6s - 48 + 30
5s - 6s = 48 + 30
-1s = -18
s = 18 yrs is sally's age now
:
Find John's age now
j = 2s - 16
j = 2(18) - 16
j = 36 - 16
j = 20 yrs is john's age now
;
What will be their ages 13 years from now?
Sally will be 31 and John will be 33
:
Check in the 2nd equation: 2(s+10) = (j+10) + 26
2(18+10) = 20 + 10 + 26
2(28) = 56
:
Did this make some sense to you? Any questions?
