PSLE The first 15 numbers of a number pattern are given.
9, 4, 2, 7, 9, 4, 2, 7, 9, 4, 2, 7, 9, 4, 2, ...
- What is the 166th number?
- What is the sum of the first 435 numbers?
(a)
Each set of numbers: 9, 4, 2, 7
Each set has 4 numbers.
Remainder: 1 → Number 9
Remainder: 2 → Number 4
Remainder: 3 → Number 2
Remainder: 0 → Number 7
166 ÷ 4 = 41 r 2
166th number = 4
(b)
Sum of each set
= 9 + 4 + 2 + 7
= 22
Number of sets
= 435 ÷ 4
= 108 r 3
Sum of the first 3 numbers
= 9 + 4 + 2
= 15
Sum of the first 435 numbers
= (108 x 22) + 15
= 2376 + 15
= 2391
Answer(s): (a) 4; (b) 2391