Question

By the end of the 5' French lesson you have learned 20 vocabulary words. Assuming you knew no wordswhen you started, write an equation that gives the number of vocabulary words you know, y, terms of theumber of lessons you have had, ×. Approximately how many words will you know after the 12' lesson?

Answer 1

Take into account that you have learnt 20 new vocabulary words after 5 lessons.

Furthermore, consider that you do not know any word at the beggin of the course.

The general form of a linear equation can be written as follow:

y = mx + b

where m is the rate of change and b is the initial value of y for x = 0 (in this case is b = 0).

The rate of change m is given by:

m = 20/5 = 4

Then, you can write for the number of words learnt, in terms of the number of lessons x, as follow:

y = 4x + 0

y = 4x

Then, to get the number of new words learnt after 12 lessons, replace x = 12 into the previous expression:

y = 4(12)

y = 48

After 12 lessons the number of new words learnt is 48