Math practice for 13 year olds - page 283 of 422

Number of problems found: 8427

Construct
Construct a rhombus ABCD if the size of the diagonal AC is 6 cm and the diagonal BD is 8 cm long.
Olda wanted
Oldrich wanted to enlarge the 9 cm x 13 cm photo so that the shorter side measured 18 cm. How big will the longer side of the photo be?
Kilometers 5972
Pavlina went on a trip on a hiking trail at an average speed of 4 km/h. Dalibor followed her an hour later and hurried at a speed of 7 km/h. How many kilometers does Dalibor cover before he catches up with Pavlina?
Father and son
When I was 11, my father was 35 years old. Today, my father has three times more years than me. How old is she?
According 5963
The numbers are arranged according to a specific logical order. What number should be in the blank a, b? 3, 7, 15, a, 63, 127, b
Twelve
Twelve students work on a week forestry brigade. One hundred spruces will receive x CZK, one hundred pine y CZK. How many receive each student in one day if they planted a total of 25,000 spruces per week and 30,000 pine trees? Express by expression.
Subsets
How many 19 element subsets can be made from the 26 element set?
14-carat 5956
14-carat gold. ... .585 per mille. In one kg. ... .585g gold. If the weight of pure gold in a ring is 7.2g, how much does the ring weigh?
Original price
The dress was reduced by 20% and, after another six months, by another 5%. It now costs 38 EUR. What was the original price of the dress?
Expressions 5949
The expressions A = 8x + 17, B = -12x-12, C = 9x-10 are given. Two-fifths of the sum of expressions A, B, and C are equal ...
Fifty-six 5943
Fifty-six seconds have already elapsed from the music recording, which was 14% of the total duration of the recording. How long the recording will still last.
R1+R2 in parallel
The resistance ratio of the first and second resistors is 3:1, and the current flowing through the first resistor is 300 mA. What current flows through the second resistor (resistors connected in parallel)?
Resistance 5939
If the resistance of the first resistor is 200 ohms and the resistance of the second resistor is 600 ohms. What will be the ratio of the electrical voltage across the first resistor to the electrical voltage across the second resistor (both are connected
Resistance 5938
If the resistance of the first resistor is 100 ohms and the voltage ratio on the first and second resistors is 2:1. What will be the resistance of the second resistor connected in series?
Sum of squares
The sum of squares above the sides of the rectangular triangle is 900 cm². Calculate the area of the square over the triangle's hypotenuse.
Fractions
Three-quarters of an unknown number is 4/5. What is 5/6 of this unknown number?
Minutes 5934
The thief stole Peter's bike and rode it down the road at 25 km/h. Peter's older brother saw it in half a minute and caught up with the thief in 5 minutes on the second lap. How fast must Peter's brother have been driving?
Individual
On the hill behind Terchová, there is a sheepfold and a shepherd lives in it. He divided two hundred of his sheep into 4 groups in a mysterious way: If he had 4 more sheep in the first group, 4 fewer in the second, 4 times more in the third, and 4 times l
Together 5931
The tank will be filled with the first inlet in 5 hours and the second in 12 hours. How long would it take to fill the tank together?
Together 5930
Vlado ate 1/5 of the candies. Marek ate 1/3 of the sweets, and Susan ate 21 candies. How many candies were together?

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