`75 xx 1/x + 25 xx 1/x = 10`
`1/x xx (75+25) = 10`
`=> 1/x xx 100 = 10`
`=> 1/x = 10/100`
`=> 1/x = 1/10`
`=> x = 10`.
`x : 75 : x + 25 : x = 10`
`x : 100 = 10`
`x = 10xx100`
`x = 1000`
x : 75 : x + 25 : x = 10
x : (75 + 25) = 10
x : 100 = 10
x = 10 x 100
x = 1000