Tutorial9.pdf

UNIVERSITI PUTRA MALAYSIA

FAKULTI SAINS


MTH 3004 PENGENALAN KEPADA MATEMATIK EKONOMI DAN PERNIAGAAN
Tutorial 9
1. Find the 20 th term and sum of the first 20 terms of the following sequences :
(a) 1, 5, 9, 13, ….
(b) 2, , , , ….
(c) 240, 220, 200,180, ….

2. If 9, x, y, 0 are in arithmetic sequence, find x and y.

3. An arithmetic series is such that the sum of its first ten terms is 20, and the sum of its
first 20 terms is 10. Find the sum of its first 40 terms.

4. Find the minimum number of terms that must be taken from the sequence 3, 5, 7, 9,….
so that the sum is more than 439.

5. How many terms of the series 1+ 4 + 7 +10 + ..... must be taken to make the sum exceed
1,000.

6. You buy a TV and agree to pay as follows : RM 150 for the first month, RM 140 for the
second month, RM 130 for the third month and so on for fifteen months.
(a) What is the 15 th payment?
(b) What is the total payment for the purchase?

7. The sum of three consecutive term x, y and z of an arithmetic progression is 45. If
1
y=( x + z ) , find the value of y.
2

th
8. The n term of a progression is np+q and the sum of n terms is denoted by Sn . Given
that the sixth term is 4 times the second term and that S3 = 12, find the value of p and q.

9. The sum of the first three terms of a geometric sequence is