張麗莉

I. Find the value of the letter “x" in each of the following.

1.85x +28= 485x -122.18÷0.3-0.2x = 5x -304

3.156- 3x =42x -4 x64.19x -8x = 6× （7x -4x）-87.5

5.80x-25x-1478= 1822

II. Write down equations for each of the following first and then find the solutions to each of them.

1.20 minus twice x， the difference is 7. Find the value of x.

2.82 divided by 2 times x and the quotient is 0.2. Find the value of x.

3.The sum of 3.7 times of a number plus 1.3 times of this number is 120. Find this number.

4.8 times of a number is 8 more than 5 times 24. Find this number.

5.Six times x plus the product of 2.5 times 4， and the sum is 25. Find the value of x.

III. Solve the algebra word problems.

1. On Saturday mornings， Annie volunteers at the hospital where her mother works. One Saturday， she answers phone calls at the information desk while the receptionist is away. Then she spends 40 minutes delivering flowers to patients5 rooms. In all， Annie volunteers at the hospital for 90 minutes that day. Solve this equation for t to find the amount of time that Annie answers phone calls.

3.Lucy had a "School's Out！" party for all her friends. She and her mother picked up a giant sub from Super Sandwich. They cut the sub into 12 equal sections. Each section was 4 inches long. Solve this equation to find the length of the giant sub.

4.A man walked from one end of a bridge to the other. When he reached 2 fifths of the length of the bridge， he was 400 meters from the midpoint of the bridge. Find the length of the bridge.

5.In Class 3， Grade 5， there are 18 more boys than girls， and the number of the boys is three times that of the girls. How many boys and how many girls are there in this class？

（參考答案見本期第39頁）