In one coffee shop, the round table can seat 10 customers and the rectangular table can seat 3 customers. During the buffet, all the tables in the coffee shop were occupied. The number of each type of tables in the coffee shop is more than 6 and less than 13. If there were 140 customers, find
(a) the number of rectangular tables
(b) the number of round tables
Rectangular tables |
Number of customers around rectangular tables |
Round tables |
Number of customers around round tables |
Total number of customers |
7 |
7 x 3 = 21 |
7 |
7 x 10 = 70 |
21 + 70 = 91 (x) |
9 |
9 x 3 = 27 |
10 |
10 x 10 = 100 |
27 + 100 = 127 (x) |
10 |
10 x 3 = 30 |
11 |
11 x 10 = 110 |
30 + 110 = 140 (✓) |
(a)
Number of rectangular tables = 10
(b)
Number of round tables = 11
Answer(s): (a) 10; (b) 11