PSLE The first 15 numbers of a number pattern are given.
4, 2, 7, 9, 4, 2, 7, 9, 4, 2, 7, 9, 4, 2, 7, ...
- What is the 282nd number?
- What is the sum of the first 427 numbers?
(a)
Each set of numbers: 4, 2, 7, 9
Each set has 4 numbers.
Remainder: 1 → Number 4
Remainder: 2 → Number 2
Remainder: 3 → Number 7
Remainder: 0 → Number 9
282 ÷ 4 = 70 r 2
282nd number = 2
(b)
Sum of each set
= 4 + 2 + 7 + 9
= 22
Number of sets
= 427 ÷ 4
= 106 r 3
Sum of the first 3 numbers
= 4 + 2 + 7
= 13
Sum of the first 427 numbers
= (106 x 22) + 13
= 2332 + 13
= 2345
Answer(s): (a) 2; (b) 2345