Main concepts are:
- Age related problems
- Distance and Speed related problems
- Unitary Method
- Ratio and Proportion
- Simple Equations
Ages for two people are given in relative manner and the absolute age will need to be found. The age can be found by writing down the relation in the form of simple equations and solving.
Example:
Pramod is twice as old as Sohan. Three years ago, he was three times as old as Sohan. How old is Pramod now? (NTSE MAT 2009)
Distance and Speed related problems
This is simple find one of distance covered, time taken or speed of any object given other information. Main formulae to remember are
Distance = speed x time
Speed = distance / time
Time = distance / speed
Also please take care of the units. Minutes may need to be converted to hours or seconds and km may need to be converted to meters. So in the formulae above use same units.
Example:
A train is moving with a speed of 92.4 km/hr. How many meters will it cover in 10 minutes. (NTSE MAT 2009)
Unitary Method
These types of questions simply give information about x number of items and asks for information about y number of items. We always solve by deriving the information for 1 item and multiplying by y.
Example:
The average salary of 20 workers in an office is Rs. 1900 per month. If manager’s salary is added the average salary becomes Rs. 2000 per month. What is the manager’s annual salary? (NTSE MAT 2009)
Ratio and Proportion
Questions on ratio and proportion are simple where either a ratio is given and actual quantities are asked or quantities are given and ratio is asked. In solving these questions sometimes formulae related to area of shapes, speed time and distance and clocks and calendars are useful.
Example:
The ratio between the length and breadth of a rectangular field is 5:4. If the breadth is 20m less than the length, the perimeter of the field is? (NTSE MAT 2009)
Simple Equations
Whatever does not fall in the categories above falls into this category. Main idea here is to clearly understand the problem and put it into equation. There are three steps. Step 1 pick an unknown item and denote it as x. Step 2, build the relation mentioned in question. Step 3, solve for x. Sometimes in the question x is not what is asked, we need to put the value of x in another equation and solve it (Ratio and proportion example above)
Example:
There were monkeys and pigeons on a tree. There were 20 heads and 48 feet. How many monkeys were there on the tree? (NTSE MAT 2009)
Most word problems are not very difficult if you carefully read it and clearly form an equation and then solve. Practice again is the key.
These and many such questions are available with full solutions at:
http://www.simplylearnt.com/practice/questions/aug15/Word-Problems
