Verified answer

Step-by-step explanation:

let the digit of no. be x and y

number = 10x+y

a/q

5(x+y)= 10x+y

5x+5y= 10x+y

5x= 4y

x/y= 4/5

hence the no.= 10x+y

= 10×4+5

= 45

product of digit= 4×5=20

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