Question

The product of the first and last digit is equal to 48

The sum of the last two digits is greater than 7

The sum of the first two digits is equal to 9

Answer 1

`a,b,c,d\ \rightarrow\ digits\ of\ number\\\\ a\cdot d=48\\c+d=7\ \ \Rightarrow\ \ c \leq 7\ and\ d \leq 7\ \ \ (*)\\a+b=9\\\\a\cdot d=48\ \ \Rightarrow\ \ (*)\ a=8\ and\ d=6\\\\a=8\ \ \Rightarrow\ \ 8+b=9\ \ \Rightarrow\ \ b=1\\\\d=6\ \ \Rightarrow\ \ c+6=7\ \ \Rightarrow\ \ c=1\\\\Ans.\ number:\ \ 8116`