SOLUTION: The sum of 3 numbers is 42. The second number is 2 more than twice the first number and the third number is 3 less than the second number. Find the 3 numbers.
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Question 268260: The sum of 3 numbers is 42. The second number is 2 more than twice the first number and the third number is 3 less than the second number. Find the 3 numbers. Answer by ankor@dixie-net.com(22740) (Show Source):
You can put this solution on YOUR website! Three numbers: a, b, c
:
Write an equation for each sentence.
:
The sum of 3 numbers is 42.
a + b + c = 42
:
The second number is 2 more than twice the first number
b = 2a + 2
:
the third number is 3 less than the second number.
c = b - 3
from the 2nd equation, replace b with (2a+2)
c = (2a + 2) - 3
c = 2a - 1
:
Find the 3 numbers.
:
a + b + c = 42
Substitute for b and c
a + (2a+2) + (2a-1) = 42
5a + 1 = 42
5a = 42 - 1
5a = 41
a =
a = 8.2 is the 1st number
then
b = 2(8.2) + 2
b = 16.4 + 2
b = 18.4
and
c = 2(8.2) - 1
c = 16.4 - 1
c = 15.4
:
Check:
8.2 + 18.4 + 15.4 = 42
