They decided to hold the party in their backyard. They have 50 sets of tables and each set has 32 chairs. There are also 31 chairs extra. How many chairs do they have for the guests?
There are 50 sets of tables and each set has 32 chairs. 
This means that there are a total of 50*32 = 1600 chairs. 
There are also 31 chairs extra. 
This means that the total number of chairs is 1600 + 31 = 1631.