Mathematics Archives

331. The current of a stream runs at the rate of 4 kmph. A boat goes 6 km and back to the starting point in 2 hours, then find the speed of the boat in still water?

A. 10 kmph

B. 21 kmph

C. 8 kmph

D. 12 kmph

✅ The correct answer is option C. 8 kmph.

332. In a river, a man takes 3 hours in rowing 3 km upstream or 15 km downstream. What is the speed of the current?

A. 2km/hr

B. 4km/hr

C. 6km/hr

D. 9km/hr

✅ The correct answer is option A. 2km/hr.

333. A room is 4 meters 37 cm long and 3 meters 23cm broad. It is required to pave the floor with minimum square slabs. Find the number of slabs required for this purpose?

A. 485

B. 431

C. 391

D. 381

✅ The correct answer is option C. 391.

334. The Ratio of the length and breadth of a plot is 3:2 .If the breadth is 40m less than the what is the parameter of the plot?

A. 480m

B. 320m

C. 400m

D. 450m

✅ The correct answer is option C. 400m.

335. The average age of a husband, wife and their child 3 years ago was 27 years and that of wife and the child 5 years ago was 20 years. The present age of the husband is___________?

A. 35 years

B. 30 years

C. 40 years

D. None of these

✅ The correct answer is option C. 40 years.

336. Two pipes A and B can fill a cistern in 20 and 30 minutes respectively, and a third pipe C can empty it in 40 minutes. How long will it take to fill the cistern if all the three are opened at the same time?

A. 19 1/7 min

B. 15 1/7 min

C. 17 1/7 min

D. 7 1/7 min

✅ The correct answer is option C. 17 1/7 min.

337. A brick measures 20 cm * 10 cm * 7.5 cm how many bricks will be required for a wall 25 m * 2 m * 0.75 m?

A. 24000

B. 23000

C. 22000

D. 25000

✅ The correct answer is option D. 25000.
25 * 2 * 0.75 = 20/100 * 10/100 * 7.5/100 * x

338. C takes 6 days to complete half of a work and D takes 5 days to complete 1/3rd of the same work. They take turns to complete the task. If C works for the first 4 days, in how many days will D complete the rest of the work without the help of C?

A. 10 days

B. 12 days

C. 8 days

D. 9 days

✅ The correct answer is option A. 10 days.
Part of work completed by C in 1 day = 1/12 Part of work completed by D in 1 day = 1/15 Part of work completed by C in 4 days

= 1/3 Work remaining = 2/3 Time taken by D to complete the work

= (2/3)÷(1/15) = 10 days

339. The area of a square is 4096 sq cm. Find the ratio of the breadth and the length of a rectangle whose length is twice the side of the square and breadth is 24 cm less than the side of the square.

A. 18 : 5

B. 7 : 16

C. 5 : 14

D. None of these

✅ The correct answer is option D. None of these.
Let the length and the breadth of the rectangle be l cm and b cm respectively. Let the side of the square be a cm.

340. While selling the watch, a shopkeeper gives a discount of 5% if he gives a discount of 7 % he earns Rs. 15 less as profit. The marked price of the watch is:

A. Rs. 697.50

B. Rs. 712.50

C. Rs. 787.50

D. None of these

✅ The correct answer is option D. None of these.