Question

16 pens costs 72 . What will be the cost of 30 pens ? How many pens can be bought for 207?​

Answer 1

cost of 16 pen = 72

cost of 1 pen = 72/16

= 4.5

cost of 30 pens = 4.5×30

= 135

and to find number of pen in 207

207/4.5

= 46

Answer 2

$\sf\underline{Step-by-step \: explanation}$

Question Correction = 16 pens cost Rs. 72. a) What will be the cost of 30 pens? b)How many pens can be bought for Rs. 207?

$\bf{Using \: proportion \: method,}$

Solving part A,

Let the cost of 30 pens be bought as x

Cost : Cost : : Pens : Pens

.....72... : ..x.... : : ..16.. : 30

● Product of extremes = Product of means

16x = 30× 72

● x =

$\tt\dfrac{72 \: \times \: 30}{16}$

$\tt{After \: cancellation...}$

Rs. 135

Hence, cost of 30 pens is Rs. 135.

Solving part B,

$\bf{Using \: proportion \: method}$

Let the pens bought in Rs. 207 be x

Cost : Cost : : Pens : Pens

.....72... : .207 : : ...16.. : ..x

●Product of extremes = Product of means.

● 72x = 207 × 16

● x =

$\tt\dfrac{207 \: \times \: 16}{72}$

● $\tt{After \: cancellation...}$

$\implies{46}$

Hence, the number of pens which can be bought in Rs. 207 are,

46.

☆ Answers,

Part A = Rs. 135

Part B = 46 pens.