Question

In a two-digit number the units digit is four times the tens digit and the sum of the digits is 10. Find the number ?

Answer 1

number $=y\times 10+x$

$x=4\left(y\right)....\left(1\right)$

$y+x=10...\left(2\right)$

$y+4y=10$

$5y=4y=10\Rightarrow y=2$

$x=8$

Number $=20+8=28$