Question

Jon weighs 148 lbs and hopes to gain 2 lbs a week. Matt weighs 198 lbs and hopes to lose 1 lb a week. How many weeks until they weight the same?

Answer 1

Jon weighs 148 lbs and hopes to gain 2 lbs a week
Formula = 148 + 2(number of weeks)
=> 148 + 2(17)
=> 148 + 34
=>  182
Matt weighs 198 lbs and hopes to lose 1 lbs a week
Formula = 198 – 1(number of week)
=> 198 - 1(17)
=> 181
On the 17th week, they’re weight will almost the same. Because Jon will weigh 182 lbs while Matt will weigh 181 pounds.
Not exactly the same but very close.

Answer 2

Let

x--------> the number of weeks

y--------> Jon weighs in lb

z--------> Matt weighs in lb

we know that

$y = 148+2x$ ----> equation $1$

$z = 198-x$ ----> equation $2$

equate equation $1$ and equation $2$

$148+2x=198-x$

$2x+x=198-148$

$3x=50$

$x=\frac{50}{3} =16.7\ weeks$

using a graph tool

see the attached figure

therefore

the answer is

On the $17$th week