Question

(a) How many right angles are there in a cubical room?

(b) What should be subtracted from ($\frac{5}{12}+\frac{3}{2}$) to get 2?

[3 MARKS]

Answer 1

(a) Answer: 1 Mark
(b) Steps: 1 Mark
Result: 1 Mark

(a) Each corner has three mutually perpendicular edges, hence forming three right angles in each corner. A room has 8 corners. Hence, there are 24 right angles in the room.

(b) Let the number to be subtracted be x.

$\Rightarrow \frac{5}{12}+\frac{3}{2}-x=2$

$\Rightarrow \frac{5+18}{12}-x=2$

$\Rightarrow \frac{23}{12}-x=2$

$\Rightarrow x=\frac{23}{12}-2$

$\Rightarrow x=\frac{23-24}{12}$
$\Rightarrow x=\frac{-1}{12}$

$\Rightarrow x=\frac{-1}{12}$