<h3>
Answer: 6</h3>
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Explanation:
"She already has two 1.5kg packs" means she already has 2*1.5 = 3 kg of food.
The statements "her pet needs 0.8 kg of food each week" and "She wants to have enough food for the next 14 weeks" tell us that she needs 0.8*14 = 11.2 kg of food total.
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Let,
x = number of packs she needs to buy
1 pack = 1.5 kg of food
x packs = 1.5x kg of food
Add on the 3 kg of food she already has to get 1.5x+3
The expression 1.5x+3 represents how much food she'll have total after buying x packs.
Set this equal to 11.2 and solve for x
1.5x+3 = 11.2
1.5x+3-3 = 11.2-3 ... subtracting 3 from both sides
1.5x = 8.2
1.5x/(1.5) = 8.2/(1.5) .... dividing both sides by 1.5
x = 5.4667 approximately
x = 6 rounding up to the nearest whole number
We round up instead of down.
This is because if x = 5, then,
1.5*x+3 = 1.5*5+3 = 7.5+3 = 10.5, but this is less than 11.2
However, if x = 6, then,
1.5*x+3 = 1.5*6+3 = 9+3 = 12 which clears the hurdle of 11.2
So this means buying 6 packages of food is the smallest amount needed to ensure her pet has enough food for the next 14 weeks.
