PSLE The first 15 numbers of a number pattern are given.
9, 6, 4, 1, 9, 6, 4, 1, 9, 6, 4, 1, 9, 6, 4, ...
- What is the 545th number?
- What is the sum of the first 308 numbers?
(a)
Each set of numbers: 9, 6, 4, 1
Each set has 4 numbers.
Remainder: 1 → Number 9
Remainder: 2 → Number 6
Remainder: 3 → Number 4
Remainder: 0 → Number 1
545 ÷ 4 = 136 r 1
545th number = 9
(b)
Sum of each set
= 9 + 6 + 4 + 1
= 20
Number of sets
= 308 ÷ 4
= 77 r 0
Sum of the first 308 numbers
= 77 x 20
= 1540
Answer(s): (a) 9; (b) 1540