Question

John deposits $\$10$ every month in his savings account. He withdraws $\$50$ from it for shopping. He now has $\$250$ left in the account. For how long has he been depositing money in his savings account?

• A. 40 months
• B. 50 months
• C. 20 months
• D. 30 months

Answer 1

The correct option is D 30 months

Amount of money John deposits in his savings account every month $=\$10$
Let the number of months he deposits the money be $x$.
Amount of money John saves in $x$ month $=10\times x=\$10x$
Amount withdrew $=\$50$
Bank balance after withdrawing $\$50=\$250$

Amount of money John saves in x months - amount of money withdrawn = bank balance after the amount is withdrawn
$\Rightarrow 10x-50=250$

Step 1: Add 50 on both sides of the equation to eliminate the constant on the left side of the equation.
$\Rightarrow 10x=300$
Step 2: Divide both sides by 10 to eliminate 10 on the left side of the equation.
$\Rightarrow x=\frac{300}{10}=30$
Hence, John has been saving for 30 months.