Click on the phrase in the word problem that describes a nonlinear rate.
Ralph's bank account started off at a meager amount. However, he quickly learned that as each year progressed, his amount saved doubled from the previous year. If he started off with $50 in his account, how much would he have in 10 years?

Question

Click on the phrase in the word problem that describes a nonlinear rate.  
Ralph's bank account started off at a meager amount. However, he quickly learned that as each year progressed, his amount saved doubled from the previous year. If he started off with $50 in his account, how much would he have in 10 years?

Mercury · Answer

old question, answering to close.

it is asking to identify a word or phrase that indicates that the rate is non-linear. recall that linear means changing by the same amount each time. however, if his savings account is *doubling* this is a non-linear increase. using the numbers from the problem, if he starts off with 50, it will double next year to 100, then double again next year to 200, etc. notice how it increased by 50 and then by 100. these are two different amounts; therefore, the rate is nonlinear.

I'm not sure if it *also* wants you to solve the problem, but just in case it does:
generic form for exponential equations:

y = ab^x

where a is the starting amount, b is the rate of growth or decay, x is time, y is the output at that x value

starting with 50 (a=50), doubling each year (b=2) for 10 years (x=10), plug these quantities into the equation and evaluate y