Ask Singapore Homework?
Upload a photo of a Singapore homework and someone will email you the solution for free.
Question
Secondary 1 | Maths
4 Answers Below
Anyone can contribute an answer, even non-tutors.
I need help with b) and c). Thank you!
c) From answer a), total dot/2 is equal to red dot.
Total dot = n x n+1
Red dot = total dot/2 = n(n+1)/2
Formula for 1+2+3....+n
1 =1
1+2 =3
1+2+3 = 6
.
.
.
n (n+1)/2
d) sum 51 to 200 = sum 1 to 200 - sum 1 to 50
Sum 1 to 200 = 200 x (200+1)/2 = 20100
Sum 1 to 50 = 50 x (50+1)/2 = 1275
Therefore, sum 51 to 200 = 20100-1275=18825
See 4 Answers
c) From answer a), total dot/2 is equal to red dot.
Total dot = n x n+1
Red dot = total dot/2 = n(n+1)/2
Formula for 1+2+3....+n
1 =1
1+2 =3
1+2+3 = 6
.
.
.
n (n+1)/2
d) sum 51 to 200 = sum 1 to 200 - sum 1 to 50
Sum 1 to 200 = 200 x (200+1)/2 = 20100
Sum 1 to 50 = 50 x (50+1)/2 = 1275
Therefore, sum 51 to 200 = 20100-1275=18825