Question

wallpaper 312 metre long and 25 cm wide is required to cover the walls of a room length of the room is 7 M and its breadth is twice its height determine the height of the room

Answer 1

Let the height of the room be h
So, its breadth =2h
Now,
Area of the required wallpaper =312m*0.25m
=78m sq
A/q
2h(l+b)=78m sq
2hm(7m+2hm)=78m sq
14hm sq+4h sq m sq=78m sq
2(7h+2h sq) m sq=78m sq
7h+2h sq=39
2h sq +7h-39=0
$2{h}^{2} + 7h - 39 = 0 \\ 2 {h}^{2} + 13h - 6h - 39 = 0 \\ h(2h + 13) - 3(2h + 13) = 0 \\( h - 3)(2h + 13) = 0 \\ h - 3 = 0 \div (2h + 13) \\ h - 3 = 0 \\ h = 3$
Now we have
2h=6
Therefore height of the room is 3m and its breadth =6m
I hope it may help you.