Question 750087
let unit place is y 
and tens place is x of two digit number

number  10x+y
and reverse number will be
10y+x
as per given conditions 
10x+y=3(x+y)+7
and
10y+x +7(x+y)+3
solving these equations 
we can get as
7x-2y=7 i
-6x+3y=3 ii
by solving both equations  elimination method
we will get 
X=3
and Y=7
two digit number whose tens place is 3 and unit place is 7
two digit number is 37
answer 37