PSLE The first 15 numbers of a number pattern are given.
9, 7, 4, 6, 9, 7, 4, 6, 9, 7, 4, 6, 9, 7, 4, ...
- What is the 255th number?
- What is the sum of the first 189 numbers?
(a)
Each set of numbers: 9, 7, 4, 6
Each set has 4 numbers.
Remainder: 1 → Number 9
Remainder: 2 → Number 7
Remainder: 3 → Number 4
Remainder: 0 → Number 6
255 ÷ 4 = 63 r 3
255th number = 4
(b)
Sum of each set
= 9 + 7 + 4 + 6
= 26
Number of sets
= 189 ÷ 4
= 47 r 1
First 1 number = 9
Sum of the first 189 numbers
= (47 x 26) + 9
= 1222 + 9
= 1231
Answer(s): (a) 4; (b) 1231