Question

A two digit number is 3 more than 3 times the sum of its digits. The tens digit is 6 less than the units digit, If t= the tens digit and u = the units digit, which system must be true?

A. t - u=6
10t + u =3t + u - 3

B. t = u - 6
10t + u = 3t + u - 3

C. t - u = 6
10t + u =3( t + u ) - 3

D. t = u - 6
10t + u = 3( t + u ) + 3

Answer 1

Ans D

The 2- digit number can be represented as 10t+u.

Given tens digit is 6 less than units digit. So t = u - 6. -----(1)

The number is 3more than 3 times the sum of its digit.

Sum of digits = t+u

So

10t+u = 3+[3(t+u)] ---------(2)

Answer 2

D.

Explanation:

t = tens digit

u = units digit

"A two digit number is 3 more than 3 times the sum of its digits."

10t + u = 3(t + u) + 3

"The tens digit is 6 less than the units digit."

t = u - 6

System of equations:

10t + u = 3(t + u) + 3

t = u - 6

Answer: D.