Using Algebra Question

Question 1:

Henry spents $30 on transportation and food every day. If the amount spent on food is 4 times that on transportation, find the amount spent on food.

Let x be the amount on Transporttion
Let 4x be the amount on food.
Atogether x + 4x = 30
5x = 30
x = 6
The mount spent on food = 4x = 4(6) = 24
The mount spent on food is $24

Question 2:

In a test, Dora has answered only 4/5 of the questions and 3 of them are wrong.

Given that each question carries 4 marks and Dora gets 68 marks in the test, how many questions are there in the test?

Let x be the number of questions.
(4/5 x – 3)4 = 68
(4/5 x – 3) = 68/4
4/5 x – 3 = 17
4/5 x= 17 +3
4/5 x= 20
x = 20(5)/4
x = 25

There are 25 questions in the test

2010-10-09 12:52:00 補充：
In question 1, one more step can be added,
5x = 30
x = 30/5 (This is an extra step added)
x = 6