Algebra word problems

Question

Phil has $100 and spends $3 of it per day. Earnest has $20 but is adding to it at a rate of $5 per day. After how many days will they each have the same amount? 

Answer 1

d represents number of days

Phil: 100 + 3d

Earnest: 20 + 5d

 

100 + 3d = 20 + 5d

 

Can you solve for d?

Answer 2

H Mimi,

 

Let x = # days it takes for their amounts to become equal.

 

Phil's money goes down like this: 100 - 3x (each day he loses $3 of the $100 he started with.

 

Earnest has his money going up like this: 20 + 5x (add on $5 a day to the $20 he started with).

 

We want to know when those amounts are equal.

 

100 - 3x  = 20 + 5x

 

80 = 8x

 

x = 10