Question

The product of digits of a two digit number is 8 and the sum of the squares of the digits is 20. If the number is less than 25. Find the number.

Answer 1

Let no be xy.

xy = 8,

x² + y² = 20,

(x+y)² - 2*xy = 20

(x+y)² - 16 = 30

(x+y)² = 36

=) (x+y) = 6, 1)

(x-y)² = x² + y² - 2xy

(x-y)² = 20 - 16

(x-y) = 2, 2)

Add both eq,

=) x = 4, y=2.

No = 42,

But it is greater than 25.

So ans = 24.

Answer 2

now solve it by yourself