In how many different ways can the letters of the word ‘STRESS’ be arranged?

A man standing on the bank of river observes that the angle subtended by a tree on the opposite bank is 60°. When he retrieves 36 m from the bank, he find that the angle is 30°. The breadth of the river is

Ram deposited a certain sum of money in a company at 12 % per annum simple interest for 4 years and deposited equal amount in fixed deposit in a bank for 5 years at 15 % per annum simple interest. If the difference in the interest from two sources is ₹ 1350 than the sum deposited in each case is

Find the least number exactly divisible by 12,15,20,27 ?

Find the sum of all prime numbers between 10 and 90.

The simple interest on an amount of 2,800 at the end of 3 years is Rs 420. What will be the simple interest at Rs 3200 for the same rate and for the same period?

The average salary, per head, of all the workers of an institution, is Rs. 60. The average salary of 12 officers is Rs. 400; the average salary, per head, of the rest is Rs. 56. The total number of workers in the in situation is 

A boat goes 30 km upstream and 44 km downstream in 10 hours. In 13 hours, it can go 40 km upstream and 55 km downstream. The speed of the boat in still water is.