Question

One street has 10 houses. There are 3 such streets and 9 independent houses.
How can we write this statement mathematically showing the number of houses?

• A. $39=3+9$
• B. $39=30+9$
• C. $39=30+90$
• D. $39=3+90$

Answer 1

The correct option is B $39=30+9$

Say:
Let us look at the options and find the correct one.

Steps:
$\bullet$ There are 10 houses on each street.
$\bullet$ There are 3 colonies, i.e., $10+10+10$.
$\bullet$ We also know that there are 9 independent houses, i.e., $10+10+10+9=30+9$.
$\bullet$ Thus, we can say, $39=30+9$.
$\bullet$ Hence, Option A is correct.

WB: If required, use the whiteboard to represent the given data.

Q: If there was 1 more house, how would it change the number of streets and independent houses?
A: If there was one more house, it would have made 10 houses, which together makes a street. Hence, there would have been 4 streets and no independent houses.