Question

One band has fewer than 40 speakers. They stack them in an arrayexactly 9 high. How many speakers could they have? Explain howyou know.

Answer 1

1) Gathering the data

Arranging 9 speakers in an array, and there's fewer than 40

Algebraically we could write

xy<40

2) Counting the 9 on the array. The other number that multiplied by 9 would be lesser than 40?

In other words, let's factor so x would be 9. The highest product between 9 and another whole number lesser than 40 is between 9 and 4

9y < 40

And y would be 4

36 < 40

2) So they have 36 speakers on the band.