SOLVING SYSTEM OF EQUATION USING SUBSTITUTION

Question

Frank weighs 160 pounds and is on a diet to gain two pounds a week so that he can make the football team. John weighs 208 pounds and is on a diet to lose three pounds a week so that he can be on the wrestling team in a lower weight class. If Frank and John can meet these goals with their diets, when will they weigh the same, and how much will they weigh at that time?

Answer 1

w = number of weeks on diet

 

for Frank

160 + 2w

 

for John

208 - 3w

 

160 + 2w = 208 - 3w

160 + 5w = 208

8w = 48

w = 6

 

In 6 weeks both shall weight the same, 172 lbs.