PSLE The first 15 numbers of a number pattern are given.
3, 2, 0, 9, 3, 2, 0, 9, 3, 2, 0, 9, 3, 2, 0, ...
- What is the 325th number?
- What is the sum of the first 420 numbers?
(a)
Each set of numbers: 3, 2, 0, 9
Each set has 4 numbers.
Remainder: 1 → Number 3
Remainder: 2 → Number 2
Remainder: 3 → Number 0
Remainder: 0 → Number 9
325 ÷ 4 = 81 r 1
325th number = 3
(b)
Sum of each set
= 3 + 2 + 0 + 9
= 14
Number of sets
= 420 ÷ 4
= 105 r 0
Sum of the first 420 numbers
= 105 x 14
= 1470
Answer(s): (a) 3; (b) 1470