PSLE The first 15 numbers of a number pattern are given.
3, 0, 5, 9, 3, 0, 5, 9, 3, 0, 5, 9, 3, 0, 5, ...
- What is the 351st number?
- What is the sum of the first 169 numbers?
(a)
Each set of numbers: 3, 0, 5, 9
Each set has 4 numbers.
Remainder: 1 → Number 3
Remainder: 2 → Number 0
Remainder: 3 → Number 5
Remainder: 0 → Number 9
351 ÷ 4 = 87 r 3
351st number = 5
(b)
Sum of each set
= 3 + 0 + 5 + 9
= 17
Number of sets
= 169 ÷ 4
= 42 r 1
First 1 number = 3
Sum of the first 169 numbers
= (42 x 17) + 3
= 714 + 3
= 717
Answer(s): (a) 5; (b) 717