IBEW Ratio and Proportion 3

Question 1

The ratio of the length to width of a rectangular electrical panel cover is 5:2. If the width is 14 inches, what is the length?

Accepted Answer

35 inches

Answer

Using the proportion 5/2 = x/14 gives x = (5 × 14) / 2 = 35 inches.

Question 2

An electrical plan calls for 3 outlets for every 150 square feet of floor space. How many outlets are needed for a 1,200 square foot area?

Accepted Answer

24

Answer

The rate is 3 outlets per 150 sq ft, so for 1,200 sq ft: (1,200 / 150) × 3 = 8 × 3 = 24 outlets.

Question 3

If the resistance of wire is directly proportional to its length, and 200 feet of wire has a resistance of 5 ohms, what is the resistance of 350 feet of the same wire?

Accepted Answer

8.75 ohms

Answer

Setting up the proportion 5/200 = x/350 gives x = (5 × 350) / 200 = 8.75 ohms.

Question 4

A union job requires 1 foreman for every 7 workers. If there are 56 workers on the site, how many foremen are required?

Accepted Answer

8

Answer

Divide the number of workers by the ratio: 56 ÷ 7 = 8 foremen.

Question 5

Materials for a job cost $420 and cover 280 square feet. How much will materials cost to cover 350 square feet at the same rate?

Accepted Answer

$525

Answer

The unit rate is $420 / 280 = $1.50 per sq ft; 350 × $1.50 = $525.

IBEW - Aptitude Test Practice Test

IBEW - Aptitude Test Practice Test

IBEW Ratio and Proportion 3