Question

Average monthly expenditure for January--June is ₹ 3200. He spends ₹ 3000 (July), ₹ 3600 (Aug), ₹ 3900 (Sept), ₹ 4200 (Oct). If November’s expenditure is $50%$ of December’s and the average for the entire year is ₹ 3200, find November’s expenditure.

• A. 1600
• B. 1400
• C. 1700
• D. 1500

Hint:

With averages across periods, convert to totals first; then apply given ratios (here, $N=\tfrac{1}{2}D$) to split the remainder.

Answer 1

The Correct Option is D

Step 1: Compute required totals.
Total for $12$ months $=12\times₹ 3200=₹ 38400.$
Total Jan--Jun $=6\times₹ 3200=₹ 19200.$
Total Jul--Oct $=₹(3000+3600+3900+4200)=₹ 14700.$
Spent till Oct $=₹(19200+14700)=₹ 33900.$
Step 2: Amount left for Nov & Dec.
Remaining $=₹(38400-33900)=₹ 4500.$ Let Nov $=N$ and Dec $=D$ with $N=\tfrac{1}{2}D \(\Rightarrow\) D=2N.$
Then $N+D=3N=₹ 4500 \(\Rightarrow\) N=₹ 1500.$
\boxed{\text{November’s expenditure }=\ ₹ 1500}