PATTERNS, FUR1 2006 VCAA 6 MC

A crystal measured 12.0 cm in length at the beginning of a chemistry experiment.

Each day it increased in length by 3%.

The length of the crystal after 14 days growth is closest to

A. `12.4\ text(cm)`

B. `16.7\ text(cm)`

C. `17.0\ text(cm)`

D. `17.6\ text(cm)`

E. `18.2\ text(cm)`

Show Answers Only

`E`

Show Worked Solution

`text(After day 1, length)\ = 12.0 xx 1.03`

♦♦ Mean mark 25%.
MARKERS’ COMMENT: The question asks for length after 14 days’ growth, not its length on the start of the 14th day.

`text(After day 2, length)\ = 12.0 xx 1.03^2`

`vdots`

`:.\ text(After day 14, length)`

`= 12.0 xx 1.03^14 `

`= 18.15\ text(cm)`

`rArr E`