Exercise 8.2
Question 1
A man got a 10% increase in his salary. If his new salary is Rs 1,54,000, find his original salary.
Sol :
Let the original salary be x. It is given that the new salary is Rs 1,54,000.
Original salary + Increment = New salary
However, it is given that the increment is 10% of the original salary.
Therefore,
Thus, the original salary was Rs 1,40,000
Q 2 - Ex 8.2 - Comparing Quantities - NCERT Maths Class 8th - Chapter 8
On Sunday 845 people went to the Zoo. On Monday only 169 people went. What is the per cent decrease in the people visiting the zoo on Monday?
Sol :
It is given that on Sunday, 845 people went to the zoo and on Monday, 169 people went.
Decrease in the number of people = 845 − 169 = 676
Percentage decrease =
Q 3 - Ex 8.2 - Comparing Quantities - NCERT Maths Class 8th - Chapter 8
Question 3
A shopkeeper buys 80 articles for Rs 2,400 and sells them for a profit of 16%. Find the selling price of one article.
Sol :
It is given that the shopkeeper buys 80 articles for Rs 2,400.
Cost of one article =
Profit percent = 16
Selling price of one article = C.P. + Profit = Rs (30 + 4.80) = Rs 34.80
Q 4 - Ex 8.2 - Comparing Quantities - NCERT Maths Class 8th - Chapter 8
Question 4
The cost of an article was Rs 15,500. Rs 450 were spent on its repairs. If it is sold for a profit of 15%, find the selling price of the article.
Sol :
Total cost of an article = Cost + Overhead expenses
= Rs 15500 + Rs 450
= Rs 15950
∴Selling price of the article = C.P. + Profit = Rs (15950 + 2392.50)
= Rs 18342.50
Q 5 - Ex 8.2 - Comparing Quantities - NCERT Maths Class 8th - Chapter 8
A VCR and TV were bought for Rs 8,000 each. The shopkeeper made a loss of 4% on the VCR and a profit of 8% on the TV. Find the gain or loss percent on the whole transaction.
Sol :
C.P. of a VCR = Rs 8000
The shopkeeper made a loss of 4 % on VCR.
This means if C.P. is Rs 100, then S.P. is Rs 96.
When C.P. is Rs 8000, S.P. =
= Rs 7680C.P. of a TV = Rs 8000
The shopkeeper made a profit of 8 % on TV.
This means that if C.P. is Rs 100, then S.P. is Rs 108.
When C.P. is Rs 8000, S.P. =
= Rs 8640Total S.P. = Rs 7680 + Rs 8640 = Rs 16320
Total C.P. = Rs 8000 + Rs 8000 = Rs 16000
Since total S.P.> total C.P., there was a profit.
Profit = Rs 16320 − Rs 16000 = Rs 320
Therefore, the shopkeeper had a gain of 2% on the whole transaction.
Q 6 - Ex 8.2 - Comparing Quantities - NCERT Maths Class 8th - Chapter 8
During a sale, a shop offered a discount of 10% on the marked prices of all the items. What would a customer have to pay for a pair of jeans marked at Rs 1450 and two shirts marked at Rs 850 each?
Sol :
Total marked price = Rs (1,450 + 2 × 850) = Rs (1,450 +1,700) = Rs 3,150
Given that, discount % = 10%
Discount =
Also, Discount = Marked price − Sale price
Rs 315 = Rs 3150 − Sale price
∴ Sale price = Rs (3150 − 315) = Rs 2835
Thus, the customer will have to pay Rs 2,835.
Q 7 - Ex 8.2 - Comparing Quantities - NCERT Maths Class 8th - Chapter 8
Question 7
A milkman sold two of his buffaloes for Rs 20,000 each. On one he made a gain of 5% and on the other a loss of 10%. Find his overall gain or loss.
(Hint: Find CP of each)
Sol :
S.P. of each buffalo = Rs 20000
The milkman made a gain of 5% while selling one buffalo.
This means if C.P. is Rs 100, then S.P. is Rs 105.
C.P. of one buffalo =
= Rs 19,047.62Also, the second buffalo was sold at a loss of 10%.
This means if C.P. is Rs 100, then S.P. is Rs 90.
∴C.P. of other buffalo =
= Rs 22222.22Total C.P. = Rs 19047.62 + Rs 22222.22 = Rs 41269.84
Total S.P. = Rs 20000 + Rs 20000 = Rs 40000
Loss = Rs 41269.84 − Rs 40000 = Rs 1269.84
Thus, the overall loss of milkman was Rs 1,269.84.
Q 8 - Ex 8.2 - Comparing Quantities - NCERT Maths Class 8th - Chapter 8
Question 8
The price of a TV is Rs 13,000. The sales tax charged on it is at the rate of 12%. Find the amount that Vinod will have to pay if he buys it,
Sol :
On Rs 100, the tax to be paid = Rs 12
On Rs 13000, the tax to be paid will be
= Rs 1560
Required amount = Cost + Sales Tax = Rs 13000 + Rs 1560
= Rs 14560
Thus, Vinod will have to pay Rs 14,560 for the T.V.
Q 9 - Ex 8.2 - Comparing Quantities - NCERT Maths Class 8th - Chapter 8
Question 9
Arun bought a pair of skates at a sale where the discount given was 20%. If the amount he pays is Rs 1,600, find the marked price.
Sol :
Let the marked price be x.
Also,
Discount = Marked price − Sale price
Thus, the marked price was Rs 2000.
Q 10 (in Old edition book), Ex 8.2 - Comparing Quantities., Solved it as a Example Question
Question 10
I purchased a hair-dryer for Rs 5,400 including 8% VAT. Find the price before VAT was added.
Sol :
The price includes VAT.
Thus, 8% VAT means that if the price without VAT is Rs 100, then price including VAT will be Rs 108.
When price including VAT is Rs 108, original price = Rs 100
Thus, the price of the hair-dryer before the addition of VAT was Rs 5,000.
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