Question 5
Lan and Điệp use matchsticks to build houses. Lan builds separate houses as in Figure 1, whereas Điệp builds one row of adjoining houses as in Figure 2.
Together they have built 20 houses using 108 matchsticks in total. How many houses did Lan build?
Together they have built 20 houses using 108 matchsticks in total. How many houses did Lan build?