Question

in a garden 1/4 were rose plant 2/3 were Jasmine and the remaing 30 were hibiscus how many plant were in the garden

Answer 1

let the total no. of plants be x....
so part of plants that were roses =x/4
part of plants that were jasmine=2x/3
no. of hebiscus=30
so ,
x-(x/4+2x/3)=30
now.....
x/12=30
so x=360......(solved)

Answer 2

Let the total no. of plants be x. 

$\frac{1}{4} x + \frac{2}{3} x + 30 = x$
$= \frac{x}{4} + \frac {2x}{3} + 30 = x$
$= \frac{3x}{12} + \frac{8x}{12} + \frac{360}{12} = x$
$= \frac{11x + 360}{12} = x$
$11x + 360 = 12 x$
$12x - 11x = x = 360$

∴ There were total of 360 plants in the garden.