A worker lays (50) bricks on the first day and (10) more bricks each next day. How many bricks will he lay on the (6)th day?

Correct answer: 100

The number of bricks laid each day forms an arithmetic progression with first term \(a=50\) and common difference \(d=10\). The sixth term is \(a_6=a+(6-1)d=50+5\times10=100\). Therefore, the correct answer is 100. Note that 90 is the number of bricks laid on the fifth day. Exam tip: Use \(a_n=a+(n-1)d\) for the nth term of an AP.