Question

1. I am a two-digit number. My tens digit

is 4 more than my ones digit. If you

multiply me by 5, the estimated

product is 300. What number

am I?

Answer 1

the answer is fifteen(15)

Answer 2

let the tens digit number be10x
then, the ones digit number be y

case1
the tens digit is 4 more then it's one digit
so , 10x=4+y. (equation 1)

case2
the number is (10x+y). {eg.10×6+5=65}

(10x+y)5=300. (equation 2)

taking value of 10x from eq.1 and putting in eq2

(10x+y)5=300
4+y+y=300÷5
4+2y=60
2y=60-4
y=56÷2
y=28

10x=4+y
10x=4+28
x=32÷10
x=3.2
so, the number is 10x+y=10×3.2 + 28
32+28=60


your answer is 60