SOLUTION: second number is 5 less than the first,thorn number is 1 more than twice the first, if the third number is 20 more than the second what are the three numbers? could you please e

Algebra.Com
Question 698261: second number is 5 less than the first,thorn number is 1 more than twice the first, if the third number is 20 more than the second what are the three numbers?
could you please explain how to do these type of problems if you can.

Answer by ankor@dixie-net.com(22740)   (Show Source): You can put this solution on YOUR website!
First, designate the 3 number as a, b, c
:
Write a equation for each statement ("is" means =)
:
"second number is 5 less than the first,"
b = a - 5
:
"third number is 1 more than twice the first,"
c = 2a + 1
:
"the third number is 20 more than the second"
c = b + 20
From first statement, we can replace b with (a-5)
c = (a-5) + 20
c = a + 15
From the last statement, we can replace c with (2a+1)
2a + 1 = a + 15
2a - a = 15 - 1
a = 14
then we know b = a - 5, therefore
b = 14 - 5
b = 9
and we know c = b + 20
c = 9 + 20
c = 29
:
Our three numbers: 14, 9, 29
:
:
Confirm this; replace the value in the 3 original equations & see they are true
c = b + 20
c = 9 + 20
c = 29
and
b = a - 5
b = 14 - 5
b = 9
and
c = 2a + 1
c = 2(14) + 1
c = 29
:
There is no set way to do these, the idea is to reduce the number of variables by substitution.
Just keep doing this until there is only one variable in the equation
Then further substitute to find the other variables.
Check your solutions in each statement.






RELATED QUESTIONS

The sum of three numbers is 26 if the second number is 3 more than four times the first... (answered by macston)
In a set of numbers, the second number is 3 more than twice the first, and the third... (answered by ikleyn)
the sum of 3 numbers is 123. the second number iis 2 more than twice the first number.... (answered by stanbon)
If a number is 20% more than the other, how much percent is the second number less than... (answered by verclau)
If a number is 20% more than the other, how much percent is the second number less than... (answered by josgarithmetic)
If a number is 20% more than the other how much percent is the second number less than... (answered by ikleyn)
If a number is 20% more than the other, how much percent is the second number less than... (answered by stanbon)
if a number is 20% more than the other, how much percent is the second number less than... (answered by Fombitz,ikleyn)
Separate the number 50 into three parts so that the second number is twice the first... (answered by checkley79)