Price of one blue pen = Rs.15
Price of one red pen = Rs.20
In shop A:
Let the number of blue and red pens sold are Ab and Ar respectively. Then,
Then, Ab + Ar = 32...(i)
And 15Ab + 20Ar = 580
3Ab + 4Ar = 116..(ii)
From (ii) - 3(i), we get
4Ar - 3Ar = 116 - 3 * 32
Ar = 20
Ab = 32 - 20 = 12
So, selling price of blue pens = 12 * 15 = Rs.180
And selling price of red pens = 20 * 20 = Rs.400
In shop C:
Let the number of blue and red pens sold are Ab and Ar respectively. Then,
Then, Ab + Ar = 20...(iii)
And 15Ab + 20Ar = 370
3Ab + 4Ar = 74..(iv)
From (iv) - 3(iii), we get
4Ar - 3Ar = 74 - 3 * 20
Ar = 14
Ab = 20 - 14 = 6
So, selling price of blue pens = 6 * 15 = Rs.90
And selling price of red pens = 14 * 20 = Rs.280
In tabular form:
| Shop | Number of pens | Selling price of (in rupees) |
| Total | Blue | Red | Total pens | Blue pens | Red pens |
| A | 32 | 12 | 20 | 580 | 180 | 400 |
| B | | | | | | |
| C | 20 | 6 | 14 | 370 | 90 | 280 |
| D | 28 | | | | | |
| E | | | | 310 | | |
Number of red pens sold by shop C = 14
And the number of blue pens sold by shop A = 12
Therefore, ratio = 14: 12 = 7: 6
Study Notes
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