Given:
Initial amount saved = $100
The amount she saves per month = $50
The total amount she has saved = $400
To find the number of months, we would subtract the initial amount from the total amount and divide it by the amount saved per month:
Hence, we have the formula:
Let the number of months she has been saving be x
Substituting we have:
Cross-Multiply:
Answer:
100 + 5x = 400 (Option A)