Question

Yohanna is conditioning all summer to be fit for the next soccer season at his high school. He incorporated walking planks into his daily workout regime. Each day, he will complete 4 more walking planks than the day before. If he starts with 5 walking planks on the first day, how many walking planks will he do on the twelfth day?

Answer 1

49 walking planks because 5+4+4+4+4+4+4+4+4+4+4+4=49

Answer 2

4 more than previous day
so
aritmetic sequence
first term is a1
common difference is d
an=a1+d(n-1)

first term is 5 planks
increases by 4 each day

an=5+4(n-1) is the equation for how many he will do on the nth day



12th day

a12=5+4(12-1)
a12=5+4(11)
a12=5+44
a12=49

49 walking planks