Advertisements
Advertisements
प्रश्न
If A is increased by 20%, it equals B. If B is decreased by 50%, it equals C. Then ______ % of A is equal to C.
Advertisements
उत्तर
If A is increased by 20%, it equals B. If B is decreased by 50%, it equals C. Then 60 % of A is equal to C.
Explanation:
Given, If A is increased by 20%, then it is equal to B.
∴ A + 20% of A = B
⇒ `A(1 + 20/100) = B`
⇒ `120/100 A = B`
⇒ `B = 6/5 A` ...(i)
If B is decreased by 50%, then it is equal to C.
∴ B – 50% of B = C
⇒ `B(1 - 50/100) = C`
⇒ `B xx 50/100 = C`
⇒ `1/2 B = C`
⇒ B = 2C ...(ii)
On comparing equations (i) and (ii), we get
`6/5 A = 2C`
⇒ `A/C = 10/6`
⇒ `C = 6/10`
⇒ `C = 3/5 A`
∴ In percentage, `C/A xx 100 = (3/5 A)/A xx 100%`
= `3/5 xx 100%`
= 60%
Hence, 60% of A is equal to C.
APPEARS IN
संबंधित प्रश्न
Mohan's income is Rs 15500 per month. He saves 11% of his income. If his income increases by 10%, then he reduces his saving by 1%, how much does he save now?
Shikha's income is 60% more than that of Shalu. What percent is Shalu's income less than Shikha's?
A school team won 6 games this year against 4 games won last year. What is the percent increase
Kayal scored 225 marks out of 500 in revision test 1 and 265 out of 500 marks in revision test 2. Find the percentage of increase in her score
Radhika bought a car for Rs 2,50,000. Next year its price decreased by 10% and further next year it decreased by 12%. In the two years overall decrease per cent in the price of the car is ______.
Increase of a number from 150 to 162 is equal to increase of ______ per cent.
2500 is greater than 500 by ______ %.
In 1975, the consumption of water for human use was about 3850 cu.km/year. It increased to about 6000 cu.km/year in the year 2000. Find the per cent increase in the consumption of water from 1975 to 2000. Also, find the annual per cent increase in consumption (assuming water consumption increases uniformly).
For an amount, explain why, a 20% increase followed by a 20% decrease is less than the original amount.
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.
Suppose a sunscreen allows 25% of the sun’s UV rays.
- What fraction of UV rays does this sunscreen block? Give your answer in lowest terms.
- Use your answer from Part (a) to calculate this sunscreen’s SPF. Explain how you found your answer.
