All MCQs

Twice the efficiency means twice the daily work rate.
Therefore, A takes half of 18 days, which is 9 days.

Worker-days remain constant for the same job.
Thus, 15 × 20 ÷ 12 = 25 workers.

B's rate is 1/8 - 1/12 = 1/24.
Therefore, B alone needs 24 days.

Their combined daily rate is 1/10 + 1/15 = 1/6.
Therefore, they complete the job in 6 days.

Daily work equals total work divided by the number of days.
Thus, A's one-day work is 1/12.

Compound growth gives 20,000 × 1.05².
The result is 22,050.

Each year, 90% of the previous value remains.
Thus, 50,000 × 0.9² = Rs. 40,500.

The taxed price is 115% of the original price.
So the original is 2,300 ÷ 1.15 = Rs. 2,000.

Commission is 6% of total sales.
Thus, 0.06 × 250,000 = Rs. 15,000.

Sales tax is 12% of Rs. 5,000, or Rs. 600.
The total payable amount is Rs. 5,600.

The selling price is 80% of the marked price.
Thus, marked price = 960 ÷ 0.80 = Rs. 1,200.

He charges for 1,000 grams but supplies only 900 grams.
Gain percentage is 100/900 × 100 = 11 1/9%.