There are 3 green balls and 6 blue balls in a box. If two balls are drawn from the box randomly, find the probability that at least one ball is green.

If the mean proportional of A and 27 is 18, then find the value of A.

If the price of rice increases by 20% and a person reduces its consumption by 20%, by what percentage will his total expenditure on rice decrease?

Find the smallest number which when increased by 20 is completely divisible by 12, 20, 15, 18 and 24.

The count of a certain breed of bacteria was found to increase at the rate of 4% per hour and then decrease by 2% per hour. Find the bacteria at the end of 2 hours if the count was 2,00,000 initially.

A typist takes 40 minutes to type 2 pages. How long (in minutes) will he take to type 110 pages?

What sum (in ₹) will earn a simple interest of ₹840 in 3 years at 20% per year rate of interest?

In an NSS college camp, there is food provision for 350 students for 40 days. If 50 more students join the camp, then for how many days will the provision last?

Manoj travels from City A to City B. If Manoj drives his car at $$\frac{1}{5}$$​of his normal speed, then he reaches City B 36 minutes late. Find the time (in minutes) that Manoj would have taken to travel from City A to City B if he drove at his normal speed.

The average of the squares of the first 83 natural numbers is

By selling an article for ₹21, a dealer makes a profit of 20%. By how much should he increase his selling price (in ₹) so as to make a profit of 50%?