4/5x - 4/10 = 2/20...multiply everything by common denominator 20
16x - 8 = 2
16x = 2 + 8
16x = 10
x = 10/16 which reduces to 5/8 <=
415.138;452.018;457.2;828.142
0.393701 is your answer :)
X=number of weeks
We can suggest this inequation:
17x>175.5
x>175.5/17>10.323>11 (the solution have to be a whole number, therefore the answer will be 11 weeks or more)
Answer: Tomas need save money during 11 weeks.