Ascience test is worth 100 points and has 25 questions. there are multiple-choice questions worth three points each and short essay questions worth 8 points each. how many short essay questions are on the test?

There are 5 short essay questions on test

Solution:

Let "a" be the number of multiple choice questions

Let "b" be the number of short essay questions

Worth of each multiple choice questions = 3 points

Worth of each short essay questions = 8 points

There are 25 questions in total

number of multiple choice questions + number of short essay questions = 25

a + b = 25

a = 25 - b --------- eqn 1

The test is worth 100 points. Theerefore, we frame a equation as:

number of multiple choice questions x Worth of each multiple choice questions + number of short essay questions x Worth of each short essay questions = 100

3a + 8b = 100 --------- eqn 2

Let us solve eqn 1 and eqn 2

Substitute eqn 1 in eqn 2

3(25 - b) + 8b = 100

75 - 3b + 8b = 100

5b = 100 - 75

5b = 25

b = 5

Thus there are 5 short essay questions on test