PSLE The first 15 numbers of a number pattern are given.
3, 7, 9, 8, 3, 7, 9, 8, 3, 7, 9, 8, 3, 7, 9, ...
- What is the 485th number?
- What is the sum of the first 248 numbers?
(a)
Each set of numbers: 3, 7, 9, 8
Each set has 4 numbers.
Remainder: 1 → Number 3
Remainder: 2 → Number 7
Remainder: 3 → Number 9
Remainder: 0 → Number 8
485 ÷ 4 = 121 r 1
485th number = 3
(b)
Sum of each set
= 3 + 7 + 9 + 8
= 27
Number of sets
= 248 ÷ 4
= 62 r 0
Sum of the first 248 numbers
= 62 x 27
= 1674
Answer(s): (a) 3; (b) 1674