Question

If the same number be added to the numbers
5, 11, 15 and 31, the resulting numbers are in
proportion. Find the number.​

Answer 1

Answer:

IF 1 IS ADDED TO NUMBER THEY COME IN PROPORTION

Step-by-step explanation:

Let the number added be x

Then,

According to question...

If x is added to the numbers they come in proportion (i. E. X:Y::A:B)

(5+x):(11+x)::(15+x):(31+x)

On watching the equation

We can derive the formula

PRODUCT OF MEANS =PRODUCT OF EXTREMES

(11+X)*(15+X)=(5+X)*(31+X)

165+11X+15X+X²=155+5X+31X+X²

X²-X²+26X-36X=155-165

-10X=-10

X= - 10

- 10

X=1