Question

In the playground of kindergarten kids, 18 children are riding tricycles or bicycles. If there are 43 wheels in all, how many tricycles are there?
7
8
9
11

Answer 1

Let's denote the number of tricycles as \( T \) and the number of bicycles as \( B \).

We have two pieces of information from the problem:

1. The total number of children (riding tricycles or bicycles) is given by the equation:
\[
T + B = 18
\]

2. The total number of wheels is given by the equation:
\[
3T + 2B = 43
\]

Now we can solve these equations step by step.

First, from the first equation, we can express \( B \) in terms of \( T \):
\[
B = 18 - T
\]

Next, we substitute this expression for \( B \) into the second equation:
\[
3T + 2(18 - T) = 43
\]

Expanding the equation:
\[
3T + 36 - 2T = 43
\]

Now simplify it:
\[
T + 36 = 43
\]

Subtracting 36 from both sides gives:
\[
T = 7
\]

Now that we have \( T \), we can find \( B \) by substituting \( T \) back into the equation for \( B \):
\[
B = 18 - T = 18 - 7 = 11
\]

Thus, the number of tricycles is \( T = 7 \).

We verify:
- Total children: \( T + B = 7 + 11 = 18 \) (correct)
- Total wheels: \( 3T + 2B = 3(7) + 2(11) = 21 + 22 = 43 \) (correct)

Therefore, the number of tricycles is \( \boxed{7} \).