# DAV Class 7 Maths Chapter 5 Worksheet 3 Solutions

The DAV Class 7 Maths Solutions and DAV Class 7 Maths Chapter 5 Worksheet 3 Solutions of Application of Percentage offer comprehensive answers to textbook questions.

## DAV Class 7 Maths Ch 5 WS 3 Solutions

Question 1.
I purchased a watch for ₹ 330 and sold it at a loss of 20%. Find S.P. of the watch.
C.P. = ₹ 330, loss = 20%, S.P. = ?
S.P. = C.P. [1 – $$\frac{\text { loss }}{100}$$] = 330[1 – $$\frac{20}{100}$$]
= 300 × $$\frac{4}{5}$$
= 264

Question 2.
By selling a T.V. for ₹ 8000, a shopkeeper loses 20% of his cost. If he sells it for ₹ 11000, what profit or loss would be there for him?
S.P. = T 8000, Loss = 20%, C.P. = ?
S.P. = C.P. (1 – $$\frac{\text { Loss }}{100}$$)
8000 = C.P. × $$\frac{4}{5}$$
8000 = C.P. × $$\frac{20}{100}$$
C.P. = 8000 × $$\frac{4}{5}$$ = ₹ 10,000
If S.P. = ₹ 11,000
∴ Profit = S.P. – C.P. = ₹ 11,000 – ₹ 10,000 = ₹ 1000
Hence the profit = ₹ 1000

Question 3.
A shopkeeper purchased a T.V. set for ₹ 9000 and sold it at a loss of 5%. Find the selling price of the T.V. Set.
C.P. = ₹ 9000, loss = 5%, S.P. = ?
S.P = C.P[1 – $$\frac{\text { loss }}{100}$$]
= 9000(1 – $$\frac{5}{100}$$)
= 9000 × $$\frac{19}{20}$$
= 450 × 19 = ₹ 8550
Hence S.P. = ₹ 8550

Question 4.
Seeta sells a dinning set to Neeta for ₹ 6000 and gains 20%, for how much should she sell it to increase her profit by another 5%?
C.P. = ₹ 6000, gain 20%, S.P. = ?
S.P = C.P.(1 + $$\frac{\text { gain }}{100}$$)
6000 = C.P. (1 + $$\frac{20}{100}$$)
6000 = C.P. × $$\frac{6}{5}$$
C.P = 6000 × $$\frac{5}{6}$$ = ₹ 5000
Profit = $$\frac{5}{100}$$ × 5000 = ₹ 250
Total S.P. = ₹ 6000 + ₹ 250 = ₹ 6250

Question 5.
Ranjan bought a second hand scooter for ₹ 6000. He spent ₹ 300 on its repairs and sold it to vineet at a profit of 10%. Vineet sold the scooter to Mukesh at a loss of 10%. At what price did Mukesh buy the scooter?
C.P. of Scooter for Ranjan = ₹ 6000
Money spent on repairing = ₹ 300
∴ Actual C.P. for Ranjan = ₹ 6000 + ₹ 300 = ₹ 6300
S.P. = C.P.( 1 +$$\frac{\text { Profit }}{100}$$)
= 6300 (1 + $$\frac{10}{100}$$) = 6930
C.P. for Vineet = ₹ 6930
S.P. = C.P. (1 – $$\frac{\text { Loss }}{100}$$) = 6930 (1 – $$\frac{10}{100}$$)
= 6930 × $$\frac{9}{10}$$ = 6237
Hence Mukesh bought the scooter for ₹ 6237

Question 6.
A man buys two pens at ₹ 20 each. He sells one at a gain of 5% and other at a loss of 5%. Find his gain or loss %.
C.P. of one pen = ₹ 20
gain = 5%
S.P = C.P.(1 + $$\frac{\text { gain }}{100}$$)
= 20(1 × $$\frac{5}{100}$$)
= 20 × $$\frac{21}{20}$$
= 21
C.P. of other pen = ₹ 20
loss = 5%
S.P. = C.P.(1 – $$\frac{\text { Loss }}{100}$$)
= 20(1 – $$\frac{5}{100}$$) = 20 × $$\frac{19}{20}$$ = ₹ 19
S.P. of the two pens = ₹ 21 + ₹ 19 = ₹ 40
C.P. of the two pens = ₹ 20 + ₹ 20 = ₹ 40
Hence there is no loss and no profit.

Question 7.
Mr. Tandon purchased a computer for ₹ 32000 and a microwave over for ₹ 6500. On computer, he lost 5% and on microwave he gained 15%. Find his total gain or loss percent.
C.P. of a computer = ₹ 32000
C.P. of a microwave oven = ₹ 6500
For Computer, S.P = C.P(1 – $$\frac{\text { Loss }}{100}$$) = 32000(1 – $$\frac{5}{100}$$)
= 32000 × $$\frac{19}{20}$$
= 1600 × 19
= ₹ 30400

For microwave oven, S.P = C.P.(1 + $$\frac{\text { gain }}{100}$$)
= 6500(1 + $$\frac{15}{100}$$)
= 6500 × $$\frac{23}{20}$$
= 325 × 23
= ₹ 7475

Combined C.P. = ₹ 32000 + ₹ 6500 = ₹ 38500
Combined S.P = ₹ 30400 + ₹ 7475 = ₹ 37875

C.P > S.P.
loss = ₹ 38500 – ₹ 37875 = ₹ 625
loss% = $$\frac{625 \times 100}{38500}=\frac{125}{77}$$% or 1$$\frac{48}{77}$$%
Hence the loss = 1$$\frac{48}{77}$$%

Question 8.
A sells a bicycle to B at a profit of 20% and B sells it to C at a profit of 25%. If C pays ₹ 1500, what did A pay for it?
S.P. = C.P. (1 + $$\frac{\text { Profit }}{100}$$)
1500 – C.P. (1 + $$\frac{25}{100}$$)
1500 = C.P. × $$\frac{5}{4}$$
C.P = 1500 × $$\frac{4}{5}$$
S.P. = C.P.(1 + $$\frac{\text { Profit }}{100}$$)
1200 -C.P.(1 + $$\frac{20}{100}$$)
1200 = C.P. × $$\frac{6}{5}$$
⇒ C.P. = 1200 × $$\frac{5}{6}$$