Test Index

Ratio and Proportion

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Question : 19 of 112

Marks: +1, -0

{P}, {Q}

{R}

are three cities. The ratio of average temperature between

{P}

{Q}

11: 12

and that between

{P}

{R}

is 9: 8 . The ratio between the average temperature of

{Q}

{R}

$22: 27$
$27: 22$
$32: 33$
none

Solution:

Concept:

The ratios share a common city

P

. Make

P

the same in both ratios to compare

Q

and

R

.

Explanation:

Given

P:Q = 11:12

and

P:R = 9:8

.

We need

Q:R

.

From

P:Q = 11:12

, we get

\frac{Q}{P} = \frac{12}{11}

.

From

P:R = 9:8

, we get

\frac{P}{R} = \frac{9}{8}

.

Multiply to find

\frac{Q}{R}

:

\frac{Q}{R} = \frac{Q}{P} \times \frac{P}{R} = \frac{12}{11} \times \frac{9}{8} = \frac{108}{88} = \frac{27}{22}

.

Thus

Q:R = 27:22

.

Answer:

The ratio between the average temperature of

Q

and

R

is

27:22

.

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