F4 Maths Quadratic Equations in One Unknown

Jacky0509

1. There are two integers. The larger integer is 3 times the smaller integer. If the two integers are decreased by 1, the sum of their reciprocals is 5/8, find the two integers.

2. Given three consecutive positive numbers x,y and z where x<y<z. If xy+yz+zx=47, find x,y and z.

3. Peter bought a number of books for $1200. If the price of each book is increased by $3, he can buy 20 books less with the same amount of money. FInd the original price of each book and the original number of books bought.

4. The F.5 graduates of Longman College agreed to share the total expenditure of $63000 for the graduation dinner. However, 10 graduates were unable to attend and each graduate had to pay $30 more on that day. How many graduates attended the graduation dinner?

Please help me, Thank you! ^^

[S]【YU】

1.
x , 3x
x-1, 3x-1
1/(x-1) + 1/(3x-1) = 5/8

2. y-1 , y , y+1

3.
P = 1200/n
(P+3)(n-20) = 1200

4. 63000/n + 30 = 63000/(n-10)