Math practice for 13 year olds - page 10 of 421

Number of problems found: 8414

A man 21
A man sells a bicycle at a profit of 25%. Had he bought it at a price less by 25% and sold it at 250 euro less then also he could have made a profit of 25%. Find cost price.
Mean proportional
If x+7 is the mean proportional between (x+3) and (x+12), find the value of x .
Three girls
Rs.1400 is divided among Amla, Bimla, and Simla so that Amla receives half as much as Bimla, and Bimla receives half as much as Simla. Then Simla's share is:
The HCF
The HCF of two numbers is 18 and their product is 12960. Their LCM will be
Missing side length
Use the Pythagorean Theorem (a² + b²=c²) to find a unknown side length: a = 5; c = 13 ; b=?
Multiple and remainder
What is the least multiple of 7, which, when divided by each one of 6,9,15,18, gives the remainder of 4 in each case?
A boat 2
A boat can travel with a speed of 13 km/h in still water.If the speed speed of stream is 4 km/h, then find the time taken 1) to go 68 km downstream . 2) to go 63 km upstream .
A passenger
A passenger train, 150 m long, passes a railway platform, 200 m long, in 35 seconds. Find: 1) speed of the train in km/h 2) the time taken by the train to pass a man cycling in the direction of the train at the rate of 9 km/h.
The first
The first 300 km of a journey is covered in 10/3 hours, and the remaining journey is covered in 8/3 hours at 75 km/h. Find the average speed of the whole journey.
An election
In an election between two candidates, one candidate secured 43% of the total votes polled and lost the election by 4900 votes. Find the total number of votes polled.
Two sets 2
If X and Y are two sets such that X ∪ Y has 50 elements, X has 28 elements and Y has 32 elements, how many elements does X ⋂ Y have?
Telephones
The cost of manufacturing x telephones by Josh Mobiles is given by C = 500 + 45x, and the revenue from selling these are given by R = 65x. How many telephones must be produced and sold in order to realize a profit?
The difference 8
The difference between the ages of two brothers is 10 years, and 15 years ago their ages were in the ratio 2:1.Find the ratio of their ages 15 years hence .
A man 20
A man sells an article at successive discounts of 10% and 5% on the listed price. Another man sells the same article at a discount of 15%.If the difference between the two selling prices be Rs 24, find the listed price of the article.
Three pipes PPM
Pipe A can fill a tank in 20 h while pipe B can fill it in 10 h and pipe C can empty the full tank in 30 h. If all the pipes are opened together, how much time will be needed to make the tank full?
Number 77
Find a number which is as much greater than 31 as it is less than 77. Many failed to do it!
Two men
2 men or 3 women can do a piece of work in 45 days. Find, in how many days 6 men and 1 women be able to complete the same work.
Wheat plus and minus
If the price of wheat is increased by 20% today, at what percent should it be decreased tomorrow, so as to bring down the price back to the original?
Known hcf and find lcm
Given that HCF (306, 657) = 9, find LCM (306, 657).
Sport field
There is a circular path around a sports field. Sonia takes 18 minutes to drive one round of the field, while Roland takes 12 minutes for the same. Suppose they both start at the same point and at the same time and go in the same direction. After how many

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