PATTERNS, FUR1 2008 VCAA 6 MC

Kai commenced a 12-day program of daily exercise. The time, in minutes, that he spent exercising on each of the first four days of the program is shown in the table below.

If this pattern continues, the total time (in minutes) that Kai will have spent exercising after 12 days is

A. `59`

B. `180`

C. `354`

D. `444`

E. `468`

Show Answers Only

`D`

Show Worked Solution

`15, 19, 23, 27\ …`

`text(AP where)\ \ \ a`	`= 15, and`
`d`	`= 19-15=4`

`S_n`	`= n/2 [2a + (n – 1) d]`
`:. S_12`	`= 12/2[2 xx 15+(12-1)4]`
	`= 6[30 + 44]`
	`= 444`

`=> D`