Question

x + 2y = 20
2x + 2y = 25
​

Answer 1

x + 2y = 20 ------(1)

2x + 2y = 25 ------(2)

subtracting equation ----(2) from ---(1) ..

→ -x = - 5

→ x = 5

substituting x = 5 in -----(1)

→ x + 2y = 20

→ 5 + 2y = 20

→ 2y = 15

$\rightarrow{y\:=\:\frac{15}{2}}$