Approximation Test-1 (Rounding off to Integers)

Answer: Option C

Explanation

By applying exact square root value we get,

$$\begin{gathered} \begin{array}{l}\sqrt{\text{1230}}\text{ + }\sqrt{\text{4230}}\text{ = ?}\end{array} \\ = 35+65= 100 \\ \hspace{0.17em}\hspace{0.17em}\hspace{0.17em}\hspace{0.17em}\hspace{0.17em}\hspace{0.17em}\hspace{0.17em}[\because \sqrt{\text{1230}}=35and\sqrt{\text{4225}}\text{ = 65]} \end{gathered}$$

Hence, Option C is correct.

Answer: Option A

Explanation

The given expression can also be written as,

= 4300 ÷20+6500 ÷13 = ?

= 215+500

= 715 ≈725

Hence, Option A is correct.

Answer: Option B

Explanation

Given that,

$40\% of 5051-\frac{3}{7}\text{th} of 999=?$

It can be written as 

50% of 5000-$\frac{3}{7}\text{th}$ of 987=?

⇒ $\frac{1}{2}$×5000-3×141=?

⇒ 2500-423

⇒ 2077≈2045

Hence, Option B is correct.

Answer: Option D

Explanation

23% of 6783 + 57% of 8431 =?

It can be written as

23% of 6800+ 57% of 8400 =?

$=\frac{23\times 6800}{100}+\frac{57}{100}\times 8400=?$

= 23×68+57×84=?

= 23×70+60×84=?

= 1610+5040=?

= 6650≈6630

Hence, Option D is correct.

Answer: Option B

Explanation

$\sqrt[3]{54821}\times \left(303÷8\right)={\left(?\right)}^2$

It can be written as

$\sqrt[3]{54872}\times \left(296÷8\right)={\left(?\right)}^2$

= 38×37=(?)² $[\because \sqrt[3]{54872}=38]$

= (?)²=38×38

= (?)=38

Hence, Option B is correct.