Advertisements
Advertisements
Question
An alloy of copper and zinc contains 45% copper and the rest is zinc. Find the weight of zinc in 20 kg of the alloy.
Advertisements
Solution
Total weight of alloy = 20 kg
Weight copper = 20 × 45% = `20xx45/100` = 9 kg
Weight of zinc = (total weight of alloy – weight of copper)
= 20 – 9
= 11 kg
APPEARS IN
RELATED QUESTIONS
Find the percentage change, when a number is changed from :
100 to 80
A tin contains 20 litres of petrol. Due to leakage, 3 litres of petrol is lost. What percent is still present in the tin?
A class has 30 boys and 20 girls. Find the percentage of girls in the class.
48 is 32% of which number?
If the difference between 75% of a number and 60% of the same number is 82.5, then find 20% of that number
When 60 is subtracted from 60% of a number to give 60, the number is
Sunscreens block harmful ultraviolet (UV) rays produced by the sun. Each sunscreen has a Sun Protection Factor (SPF) that tells you how many minutes you can stay in the sun before you receive one minute of burning UV rays. For example, if you apply sunscreen with SPF 15, you get 1 minute of UV rays for every 15 minutes you stay in the sun.
A label on a sunscreen with SPF 30 claims that the sunscreen blocks about 97% of harmful UV rays. Assuming the SPF factor is accurate, is this claim true? Explain.
Madhu’s room measures 6 m × 3 m. Her carpet covers 8 m2. What per cent of floor is covered by the carpet?
Weight of Nikhil increased from 60 kg to 66 kg. Then, the increase in weight is ______ %.
In a debate competition, the judges decide that 20 per cent of the total marks would be given for accent and presentation. 60 per cent of the rest are reserved for the subject matter and the rest are for rebuttal. If this means 8 marks for rebuttal, then find the total marks.
