AC Lim's answer to LC Tan's Primary 3 Maths Singapore question.
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Hope this helps
Date Posted:
2 years ago
I don’t understand the diagram. Can you explain it?
Look at white line...
Person number 1 will say HELLO to person number 2
Person number 3
Person number 4
Person number 5
.
.
.
.
Person number 10
Total HELLO = 9
THEN person number say Hello to
Person number 3
Person number 4
Person number 5
.
.
.
.
Person number 10
Total hello = 8....
And so on...
Therefore, total all hello
9+8+7+6+5+4+3+2+1 = 45
Person number 1 will say HELLO to person number 2
Person number 3
Person number 4
Person number 5
.
.
.
.
Person number 10
Total HELLO = 9
THEN person number say Hello to
Person number 3
Person number 4
Person number 5
.
.
.
.
Person number 10
Total hello = 8....
And so on...
Therefore, total all hello
9+8+7+6+5+4+3+2+1 = 45
Why is it not each of them say hello to 9 people? Instead of 9 times, 8 times, 7 times, Etc?
Ah.. when person number 1 say hello to person number 2...
Person number 2 will not say Hello again to person number 1...
Because 1-2 or 2-1 is already done
Person number 2 will not say Hello again to person number 1...
Because 1-2 or 2-1 is already done
When they met and said HELLO to each other, meaning 1 met 2, both say HELLO, count as one.
Anyway, for his question not very clear about number of HELLO said.
Normally, question will use shake hand to each other once when they meet.
Anyway, for his question not very clear about number of HELLO said.
Normally, question will use shake hand to each other once when they meet.
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