Question

6. A number consists of two digits whose

sum is 8. If 18 is subtracted from the
number the digits interchange their places,
then what is the number?
(a) 42
(b) 35
(c) 53.
(d) 44​

Answer 1

• Answer:

(c) 53

• Explanation:

Hi there !

we have a number ab

a + b = 8

ab - 18 = ba

10a + b - 18 = 10b + a

10a - a + b - 10b = 18

9a - 9b = 18 | + (9a + 9b)

9a + 9a - 9b + 9b = 18 + 9(a + b)

18a = 18 + 9×8

18a = 18 + 72

18a = 90

a = 90 : 18

a = 5

a + b = 8

5 + b = 8

b = 8 - 5

b = 3

ab = 53

Good luck !