Math Word Problems Demystified - A Self Teaching Guide

TYPE 1: FINDING THE PART

In type 1 problems, you are given the base and rate and you are asked to find
the part.

EXAMPLE:There are 30 students in a classroom. If 20% of them are absent
today, how many students are absent?

SOLUTION:

GOAL: You are being asked to find the number of students who are absent.

STRATEGY: Draw the circle and place 20% in the lower left portion of the
circle and 30 in the lower right portion of the circle since it is the total number
of students in the class. To find the part, useP¼RB. See Figure 5-3.

IMPLEMENTATION: Substitute in the formula and solve forP.

P¼RB

P¼20% 30

P¼0.20 30

P¼6 students

Hence, 6 students are absent.

EVALUATION: Since 20%¼^15 and^15 of 30¼6, the answer is correct.

Fig. 5-3.

LESSON 5 Using Percents 45