# Decimal Numbers Quiz Set 010

### Question 1

What is x in \${722/0.0722} = {7.22/x}\$?

A

\$7.22 × 10^{-4}\$.

B

\$7.22 × 10^{-3}\$.

C

\$7.22 × 10^{-2}\$.

D

\$7.22 × 10^{-5}\$.

Soln.
Ans: a
Transposing, x = \$7.22 × {0.0722/722}\$ which gives 0.000722, which, in scientific form is \$7.22 × 10^{-4}\$.

### Question 2

What is \$3.914 - (-0.8) + 0.09 - (-0.03)\$?

A

+4.834.

B

-4.834.

C

+4.348.

D

-4.348.

Soln.
Ans: a

The given expression is same as \$3.914 + 0.8 + 0.09 + 0.03\$, then by simple addition we get \$3.914 + 0.8 + 0.09 + 0.03 = 4.834\$.

### Question 3

What is y in \$9.073 + 0.8 + y = 0.02\$?

A

-9.853.

B

-8.853.

C

-7.853.

D

-10.853.

Soln.
Ans: a

y = 0.02 - (0.8 + 9.073) = -9.853.

### Question 4

What is \${(-79) × 6.5 - 54 × (-2.6)}/1.2\$?

A

\$-310{11/12}\$.

B

\$+310{11/12}\$.

C

\$-310{7/12}\$.

D

\$+310{7/12}\$.

Soln.
Ans: a

Observe that all fractional numbers are having one digit to the right of the dot. So we can cancel all the dots and get a plain expression: \${(-79) × 65 - 54 × (-26)}/12\$. We can now simpilfy the minus signs to get \${(54 × 26) - (79 × 65)}/12\$ which equals \${-3731/12}\$, which is same as: \$-310{11/12}\$

### Question 5

What is x in \$0.083/x = 0.0083\$?

A

10.

B

1.

C

100.

D

0.1.

Soln.
Ans: a

The expression becomes \$x = {83/83} × {10000/1000}\$ = 10. 