Let’s solve this step by step.
We are told that there are 10 girls in a line, and they are holding hands to form a human chain. The first girl is at the front, and the last girl is at the back. We need to find out how many hand-holds (or connections) there are between them.
Think about it like this:
- If there are 2 girls, they hold hands once → 1 connection.
- If there are 3 girls: Girl1–Girl2–Girl3 → 2 connections.
- If there are 4 girls: Girl1–Girl2–Girl3–Girl4 → 3 connections.
Do you see the pattern?
Every time we add one more girl, we add one more hand-hold — but only if she’s added to the end of the line.
So for n girls in a straight line, the number of hand-holds is always
n - 1.
Why? Because each girl (except the last one) holds hands with the next girl. So the first girl connects to the second, the second to the third, ..., up to the ninth connecting to the tenth. That’s 9 connections total.
Let’s count manually for 10 girls:
Girl1 – Girl2 → 1
Girl2 – Girl3 → 2
Girl3 – Girl4 → 3
Girl4 – Girl5 → 4
Girl5 – Girl6 → 5
Girl6 – Girl7 → 6
Girl7 – Girl8 → 7
Girl8 – Girl9 → 8
Girl9 – Girl10 → 9
That’s 9 hand-holds.
Also, the problem says “the first girl is at the front” and “the last girl is at the back” — which confirms it’s a straight line, not a circle. In a circle, it would be 10 hand-holds, but here it’s a line.
So the answer is 9.
Final Answer: 9
Parent Tip: Review the logic above to help your child master the concept of introduction to genetics worksheet answers.
