# Percentages + mass - math problems

#### Number of problems found: 86

• KOH
How many g of 20% KOH solution do we need to mix with 500 g of 30% KOH solution to obtain a 25% KOH solution?
• Salt solution
Calculate the weight of a 50% salt solution that we prepare from 120 g of salt.
• Beef taxation
How much should the price of 2.5 kg of beef change, which in December cost € 5.71 per 1 kg if VAT changed from 20% to 10%. how much will 2.5kg cost from January?
• Shen's
Shen's chocolate bar is 54% cocoa. If the weight of the chocolate bar is 54 grams, how many grams of cocoa does it contain? Round your answer to the nearest tenth.
• Feed to hay
How many tons of water do we have to dehydrate from 8 tons of feed, if the original moisture is 54 percent, to get hay with a moisture content of 15 percent? Round to two decimal places.
• Base of percentages
7% of the base is 35 kg. What is 39% of that base?
• Electric cooker
During which time t does an electric cooker with power input P = 500 W and with efficiency n = 75% heat water with mass m = 2 kg and temperature t1 = 10°C to the boiling point (t2 = 100°C). The specific heat capacity of water is c = 4 180 J. Kg-1. K-1
• Natural fertilizer
The rectangular garden measuring 120m and 60m was fertilized with 16kg of natural fertilizer. Natural fertilizer contains 45% organic matter. How much organic matter falls on 1 m2 of garden?
• The water barrel
The water barrel weighs 122 kg. If we pour 75% of the water out of it, it will weigh 35 kg. What is the weight of the barrel?
• Water percent
A 15 g sample of the substance contains 70% water. After drying, the substance reduced the weight to 9 g. What percentage of water is now in the sample?
• Chestnuts
Three divisions of nature protectors participated in the collection of chestnut trees.1. the division harvested 1250 kg, the 2nd division by a fifth more than the 1st division and the 3rd division by a sixth more than the second division. How many tons of
• Nitrogen
One bag of urea containing 46 percent nitrogen weighs 25 kg. How many bags have to be purchased for fertilizing a field of 41003 square meters if the nitrogen dose is 50.0 kg per hectare?
• The farm
The farm harvested 390 tons of grain. Wheat was 15% more than barley, and rye was 126 tons less than wheat and barley combined. How many tons of wheat, how many tons of barley, and how much rye did the team get?
• Washing powder
A 10-kilogram pack of washing powder is M euros more expensive than a 5-kilogram pack of the same powder. A 5-kilogram package costs P euros. Five kilos of packaging is not worth it, because it is more expensive than half the price of 10 kilos. How much i
• Apple variete
This year, my uncle harvested 350 kg of apples, including 105 kilograms of Ontario, and the rest is Jonathan. Determine what percentage of the Jonathan apples.
• Butter fat
A quarter of kg butter contains 82% fat. How many grams of fat are in four cubes of butter?
• Water in vegetables
Tomatoes in the store contain 99% water. After being transported to the shop, they were slightly dried and contained only 98% of water. How many kgs of tomatoes are in the store if there were 300 kg in stock?`
• Camel and water
84% of the camel's weight is water. After drinking, its weight increased to 832 kg, and water accounted for 85% of its weight. How much did it weigh before drinking?
• Copper sulphate
How much g of water do we have to add to 240 g of an 84% CuSO4 solution to produce a 60% solution? (Express the mass of crystalline CuSO4 in the original solution and in the resulting solution and compare them. )
• Power input
The construction lift lifted a load weighing 300 kg to a height of 12 m with a uniform movement. How long has it taken for the load to be lifted if the efficiency is 75% and the engine has a power input of 5 kW?

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