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

**Problem**

**Problem**

Three parts of alcohol A is mixed with two parts of alcohol B and sold at $110 per liter at a 10% profit. If alcohol A cost $20 more per liter than alcohol B, what is the price of alcohol A per liter?

- $104
- $115
- $106
- $108
- $110

**The Usual Method**

[contentblock id=google-adsense-post]

Let price of alcohol A be $*a* / liter

And that of alcohol B be $*b* / liter

Also cost of mixture = = $100 (1.1 is due to 10% profit)

By Alligation rule:

= $108

**(Ans: 4)**

*Estimated Time to arrive at the answer = 60 seconds.*

**Using Technique**

[contentblock id=google-adsense-post]

Note that 3 : 2 can also be written as 6 : 4 or 60 liter and 40 liters. Hence total of 100 liters. Assuming that 100 liters costs $100 ($110 less 10% profit). Of this $100, $60 belongs to alcohol A and $40 to alcohol B. (Since difference of cost of the two alcohols is $20)

This means that the price of alcohol A is a multiple of 6. The only value from the options which is a multiple of 6 is $108 of option ‘4’.

**(Ans: 4)**

*Estimated Time to arrive at the answer = 15 seconds.*

[starrater tpl=10]

[contentblock id=smartmath-blockquote]