11. Determine the number of multiples of 7 between:
a. 14 and 210
b. −51 and 348
a.
210 = 14 + 7n subtract 14 from both sides
196 = 7n divide both sides by 7
28 = n
However....since "between" is stated, we need to subtract 1 from this = 27 multiples of 7 between 14 and 210
b. similarly
348 = -51 + 7n add 51 to both sides
399 = 7n divide both sides by 7
57 = n
Suntract 1 from this
56 multiples of 7 between - 51 and 348