he buys one bag of dog food every 4 weeks so on dog food he spends 67.59 each week
7×1.29=9.03 in one week he spends 9.03 on canned food, so in four weeks he spends 36.12 on canned food
to find how much he spends in 4 weeks add the value of the dog food and the value of the canned food together
36.12+67.59=103.71
In four weeks Bruce spends $103.71