a)

44 Days / 7 = 6 R2  ***(6 full weeks and extra 2 days, Since it start on Monday)

6 Weeks = 6 Sundays

Sunday only buy Black = 6 * $1

                                           = $6

Total Spend on Red and Blue = $74.70 – $6

                                                      = $68.70

b)

Days buying Blue and Red = 44 – 6

                                                 = 38 Days

3 pack a day = 38 * 3

                       = 114

If all is Red Pack = 114 * $0.40

                                = $45.60

Difference from Total of Blue and Red = $68.70 – $45.60

                                                                       = $23.10

Price difference of Blue and Red Pack = $0.70 – $0.40

                                                                     = $0.30

Total Blue Pack = 23.10 / 0.30

                             = 77 Blue Pack

tq!!