Categories
Ratio Proportion Smart Math

[Smart Math] Ratio Proportion Problem 49

Here’s and example of a SMART MATH problem for RATIO PROPORTION.

Ratio Proportion

Problem

A, B and C are mixed together and their volumes are in the ratio 4 : 5 : 6 respectively. If the weights of equal volumes of A, B and C are in the ratio 2 : 3 : 4, what is the weight of the heaviest substance, if the weight of the mixture is 1123.84 lbs.

  1. 573.88 lbs
  2. 673.88 lbs
  3. 473.88 lbs
  4. 773.88 lbs
  5. cannot be determined

The Usual Method

[contentblock id=google-adsense-post]

The ratio of weights of A, B and C in the mixture is 4\times 2:5\times 3:6\times 4 = 8 : 15 : 24.

From this it is obvious that C will have the most weight. Hence the quantity of C in the mixture is: \frac{24}{8+15+24}\times 1123.84

=\frac{24}{47}\times 1123.84= 573.88 lbs

(Ans: 1)

Estimated Time to arrive at the answer = 60 seconds.

Using Technique

[contentblock id=google-adsense-post]

First get the ratio of weights of A, B and C in the mixture i.e. 8 : 15 : 24 ( 4\times 2:5\times 3:6\times 4)

From this it is obvious that quantity of C is approximately equal to that of the sum of A and B. In other words, C constitutes almost half of the total mixture. Hence, just divide 1123.84 by 2. This can be done by approximation by dividing 1120 by 2 i.e. 560. Hence the answer should be close to 560. The only option closest to it is 573.88 lbs which is the answer.

(Ans: 1)

Estimated Time to arrive at the answer = 30 seconds.
[starrater tpl=10]

[contentblock id=smartmath-blockquote]

Leave a Reply

Your email address will not be published. Required fields are marked *