Math practice for 13 year olds - page 17 of 420

Number of problems found: 8391

An adventurer
An adventurer makes 2/5 of a car trip, 1/3 on horseback, and the rest on foot. He walks 80 km. What is the total length of your route?
The test 3
The provided test marks for a small class of student are as follows Don 70%, Jody 68%, Raz 65% and that of Max is not provided. If the class average is 75%, what is Max test marks?
Two persons
Two persons are walking beside a railway track at respective speeds of 2 and 4 km per hour in the same direction. A train came from behind them and crossed them in 90 and 100 seconds, respectively. Find the length of the train.
20 men
20 men are supposed to complete a work in 10 days. After working for 5 days, they realize that only one-fourth of the work is done. How many more men they need to employ to complete the work on time?
Offset the mean
The mean of 16 numbers is 8. If 2 is added to every number, what will be the new mean?
Plasticine cuboid
Paul makes a cuboid of plasticine with sides 5 cm, 2 cm, and 5 cm. How many such cuboids will he need to form a cube?
To percentages
Convert the following ratios to percentages. (a) 3 : 4 (b) 2 : 3 (c) 5/8 (d) 15/16
Overtime and salary
An employee earns R150 per hour, and the agreed normal working hours are 45 hours per week. Overtime is paid at 1 1/2 of the normal rate. Suppose Dave works 52 hrs during the first week of March. What will the total earnings for that particular week be?
Double sides
If each side of a triangle is doubled, then find the ratio of the area of the new triangle thus formed to the given triangle.
Manday, manhour
Job problem: 10 men can make 20 toys in 12 days working 12 hours a day.Then, in how many days can 24 persons make 32 toys working 16 hours a day?
Tricky result
Classic adding with percentages: Evaluate 28% of 450 + 45% of 280
Two chords 6
A chord PQ is 10.4cm long, and its distance from the center of a circle is 3.7cm. Calculate the length of a second chord RS, which is 4.1cm from the center of this circle.
Numerator and denominator
If the numerator of a fraction is increased by 200% and the denominator of the fraction is increased by 150%, the resultant fraction is 9/35. What is the original fraction?
Two coins
Two coins are tossed simultaneously. What is the probability of getting (i) At least one head? (ii) At most one tail? (iii) A head and a tail?
Katy bought
Katy bought 4/5 kg of oranges, 2 1/2 kg of bananas, and 1 1/2 kg of apples every day. How many kilograms of fruit did she buy each day?
Walnuts 2
There are 6 2/3 pounds of walnuts in a container, which will be divided equally into containers that hold 1 1/2 pounds. How many containers will walnuts fill?
The marathon
Twelve athletes are joining the Topolcany Marathon Event. How many ways can the first, second, and third placers be chosen?
A rope
A 75m piece of rope needs to be cut in a ratio of 1:4. What is the length of each piece?
Closer to one
Here are two sums: A=1/2 + 1/3 and B=1/5 + 1/3. Which of the two sums is closer in value to 1? You must show your work and state clearly whether the answer is A or B.
Lara's sequence
Lara starts with a number less than 20. She divides it by 2 and adds 6. She then divides this result by 3. Her answer is 4.5. What number does she start with?

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