Arrange fractions in descending order

Answer: Option C

Explanation:

2/3 = .66, 3/4 = .75, 4/5 = .8 and 5/6 = .833

So biggest is 5/6 and smallest is 2/3

Their difference is 5/6 - 2/3 = 1/6

Answer: Option B

Explanation:

1/(60*60) = 1/3600 = .0027

Answer: Option B

Answer: Option C

Explanation:

Can be easily solved with following formula
\begin{aligned}
a^2 - b^2 = (a - b)(a + b)
\end{aligned}

Answer: Option D

Explanation:

As per given equation we can solve like this :

\begin{aligned}
= \frac{8 - 2.8}{1.3} \\
= \frac{5.2}{1.3} = \frac{52}{13} \\
= 4
\end{aligned}