Amira has $80. sasha has $40.
in how many months will they both have the same amount of money if amira saves $40 per month and sasha saves $50?

Given:
Amira = 80
Sasha = 40

Amira saves  40 per month
Sasha saves 50 per month

Let x be the number of months.
Amira = 80 +  40x
Sasha = 40 + 50x

Amira = Sasha
80 + 40x = 40 + 50x
40x - 50x = 40 - 80
-10x = -40
x = -40/-10
x = 4

Amira = 80 + 40x = 80 + 40(4) = 80 + 160 = 240
Sasha = 40 + 50x = 40 + 50(4) = 40 + 200 = 240

It would take them 4 months to have the same amount of savings.