Math practice for 13 year olds - page 11 of 435
Number of problems found: 8682
- Two pipes 3
Two pipes, A and B, can fill a tank in 15 minutes and 20 minutes, respectively. Both pipes are opened together. After 4 minutes, pipe A is turned off.What is the total time required to fill the tank? - Three 262
Three farmers, A, B, and C, hire meadow for Rs 1460. Farmer A puts in 10 cows for 20 days, farmer B 30 cows for 8 days, and farmer C 16 cows for 9 days. Find the rent paid by each one of them. - Days, hours, minutes
Add the following: 1 day 18 hr 45 m 55 sec, 13 hr 55 m 58 sec and 23 hr 49 m 45 sec - Factorial divisible by 75
Find the least positive integer n such that n! is divisible by 75. - The average 13
The average of 6 consecutive odd numbers is 64. Find the greatest number. - A conical
A conical tent can accommodate 11 people. Each person needs 4 m² of space on the ground and 20 m³ of air to breathe. Find the height of the tent. - The size 3
The size of a wooden block is 15cm × 12cm × 20cm. How many such blocks will be required to construct a solid wooden cube of minimum size?
- Find area 2
Find the area of the green region in the given picture. Dimensions are shown. - Three athletes A, B and C start at the same time in the same direction to run around a circular stadium. A completes a round in 252 seconds, B in 308 seconds and C in 198 seconds, all starting at the same point. After what time will they meet again at the starting point
- Two cats
Sally has 2 cats. Each cat eats 1/4 of a tin of cat food each day. Sally buy 7 tins of cats food. How many days did she feed her 2 cats? Show your work. - Carol 3
Carol reduces the size of a photo by 30%. If the length of each side is 12 cm, what is the length of the side of the new photo? - Divisors 7 If 540=2²×3³×5, what is the number of all factors of 540?
- Milk with water
How many liters of water are to be mixed in 12 liters of milk costing Rs 40 per liter so that it can be sold at Rs 32 per liter? - Slant height 3
The frustum of a right circular cone has the diameters of base 10 cm of top 6 cm and a height of 5 cm. Find the slant height. - Melting 3 cubes The sides of the three metal cubes are 30 cm, 40 cm, and 50 cm, respectively. Find the side of the new cube formed by melting these cubes together.
- Two angles
If one angle of a parallelogram is 24° less than twice the smallest angle, then find the largest angle of the parallelogram. - Students 48
If 80% of the students of a school are boys and 225 are girls, find the number of all students. - Three workers
A can do a work in 16 hours, and B alone in 24 hours. If A, B, and C work together and finish it in 8 hours, then C alone can finish it in how many hours? - Average cost
A man bought 1 dozen banana at Rs 60 and 8 apples at Rs 120 . What is the average cost of each? - A man 19
A man buys apples at a certain price per dozen and sells them at eight times that price per hundred, find his gain or loss percent
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