Decimal Numbers Quiz Set 019

Question 1

What is x in \$0.003/x = 0.01\$?

A

0.3.

B

0.03.

C

0.003.

D

3.0.

Soln.
Ans: a

The expression becomes \$x = {3/1000} × {100}\$ = 0.3.

Question 2

What is \${8.00^3 - 0.90^3}/{8.00^2 + 7.200 + 0.90^2}\$?

A

7.10.

B

6.95.

C

7.56.

D

6.56.

Soln.
Ans: a

We know \${a^3 - b^3}/{a^2 + ab + b^2}\$ is same as \${(a - b) × (a^2 + ab + b^2)}/{a^2 + ab + b^2}\$ which is same as a - b. So we get a - b = 8.00 - 0.90 = 7.10.

Question 3

What is 0.0029 × 0.94?

A

\$2.726 × 10^{-3}\$.

B

\$2.726 × 10^{-4}\$.

C

\$2.726 × 10^{-2}\$.

D

\$2.726 × 10^{-5}\$.

Soln.
Ans: a

Question 4

For what value of x would this expression be a perfect square: \$2.3 × 2.3 - x × 2.3 + 0.9 × 0.9\$?

A

1.8.

B

2.3.

C

0.9.

D

0.23.

Soln.
Ans: a

Comparing the given expression with \$a^2 - 2 × a ×b + b^2 = (a - b)^2\$, we see that if a = 2.3, and b = 0.9 then by inspection, x should be equal to 2b = 2 × 0.9 = 1.8.

Question 5

What is x in \${846/0.0846} = {8.46/x}\$?

A

\$8.46 × 10^{-4}\$.

B

\$8.46 × 10^{-3}\$.

C

\$8.46 × 10^{-2}\$.

D

\$8.46 × 10^{-5}\$.

Soln.
Ans: a
Transposing, x = \$8.46 × {0.0846/846}\$ which gives 0.000846, which, in scientific form is \$8.46 × 10^{-4}\$. This Blog Post/Article "Decimal Numbers Quiz Set 019" by Parveen (Hoven) is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.
Updated on 2019-08-18.