Answer:
Step-by-step explanation:
Amount paid by Joanne before promotion = 74 + 59 + 69 = $ 202
a) Amount saved if she switches to "3 for 129 plan" = 202 - 129 = $ 73
Percentage of saving = [tex]\frac{73}{202}*100[/tex] = 36.13 = 36%
b) Amount saved after the first year = 202 - 139 = $ 63
Percentage of saving = [tex]\frac{63}{202}*100[/tex] = 31.18 = 31%