Question

what no. must be subtracted from each of the no.s 31, 19. 13, 10 so that they are in proportion?

Answer 1

Answer:

Step-by-step explanation:

Let, the required number be x.

To numbers to be in proportion

Product of extremes = Product of means

(31-x)(10-x) = (19-x)(13-x)

310-31x-10x+x²= 247-19x-13x+x²

310-41x = 247-32x

310-247 = -32x+41x

63 = 9x

63/9 = x

7 = x

Answer: 7 must be subtracted from each of the number.

Answer 2

Answer:

Let the number to be subtracted be x.

Then, (31 - x) : (19 - x) : : (13 - x) : (10 - x)

(31 - x) (10 - x) = (19 - x) (13 - x)

310 - 31x - 10x + x² = 247 - 19x - 13x + x²

310 - 41x = 247 - 32

- 41x + 32x = 247 - 310

- 9x = - 63

x = 63/9

x = 9

Ans: Hence, 7 must be subtracted from each of the number to be in proportion.