SOLUTION: Keith weighs 20 kg more than Beth, while Henry weighs 30 kg less than twice as much as Beth. If Keith and Henry weigh the same, how much does Beth weigh (in kg)?

Algebra ->  Functions -> SOLUTION: Keith weighs 20 kg more than Beth, while Henry weighs 30 kg less than twice as much as Beth. If Keith and Henry weigh the same, how much does Beth weigh (in kg)?      Log On


   



Question 56994: Keith weighs 20 kg more than Beth, while Henry weighs 30 kg less than twice as much as Beth. If Keith and Henry weigh the same, how much does Beth weigh (in kg)?
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
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Keith weighs 20 kg more than Beth, while Henry weighs 30 kg less than twice as much as Beth. If Keith and Henry weigh the same, how much does Beth weigh (in kg)?
Let K = Keith's weight; B = Beth weight; H = Henry's weight
:
Write an equation from each statement
:
"Keith weighs 20 kg more than Beth,"
K = (B + 20)
:
"Henry weighs 30 kg less than twice as much as Beth."
H = (2B - 30)
:
"If Keith and Henry weigh the same, how much does Beth weigh (in kg)?"
It says: K = H
:
Substitute (B+20) for K and (2B-30) for H, you have simple equation. Find B
B + 20 = 2B - 30
20 + 30 = 2B - B
50 = B
:
Beths weight is 50 kg
:
To check our solution:
50 + 20 = 2(50) - 30
7O = 100 - 30, Henry & Keith's weight