LazyMaths.com

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

Problem

A can give B a 30 meters start and C an 80 meters start in a kilometer race. What start can B give to C in the same race?
(1 Kilometer = 1000 meters)

1. 50 meters
2. 61 meters
3. 52 meters
4. 45 meters
5. 40 meters

The Usual Method

When A travels 1000 meters,

B travels 970 meters and

C travels 920 meters.

Hence, when B has to travel 1000 meters, C will travel meters.

This comes from cross multiplication as shown below:

A             B              C

1000     970       920

1000       x

= or 948.45 meters

Therefore B can give a start of 1000 – 948.45 = 51.55 meters 52 meters

(Ans: 3)

Estimated Time to arrive at the answer = 60 seconds

Using Technique

From the data in the question, it is clear that the descending order of speed is A>B>C, i.e. A being the fastest, followed by B and C is the slowest. Also in a race of 970 meters, B can give a start of 50 meters (970 – 920) to C, Hence, it is obvious that in a 1000 meters race, the start for C has to be proportionately greater than 50 as 1000 is greater than 970. Hence, the answer has to be little over the difference of 970 and 920 meters or 50 meters; plus something. Looking at the options, the only option matching this condition is option ‘3’ or 52 meters

(Ans: 3)

Estimated Time to arrive at the answer = 10 seconds

We hope this helps you in getting to the answer faster. You can apply this technique in the exams and get to the answer before anyone else can.

If you like this
- Support us by donating
- Share it with your friends

Want more of these? Click SMART MATH

Wanna learn from other resources? Head to our MORE MATH page

You can also join OUR CLASSES and learn hundreds of such techniques. Learn to apply them in your exams and even in everyday life! We offer classroom training for SAT, GRE, GMAT and many more exams.

Is this technique really smart? Don’t forget to rate this technique

Tell us what you think. How can we improve? Feel free to comment or ask questions. We can be reached at math(at)lazymaths(dot)com

No related posts.