answer:The cost of the new iPhone is 800. Carrie can trade in her Samsung Galaxy for 240. She can make 80 per week babysitting. To calculate how many weeks she needs to work, we need to subtract the trade-in value from the cost of the iPhone: 800 - 240 = 560. Then, we divide the remaining amount by her weekly earnings: 560 / 80 = 7. So, Carrie needs to work 7 weeks before she can purchase the iPhone. 7 The answer is: 7

answer:To find 5ast2, we substitute a=5 and b=2 into the expression 3a + 4b - ab. Doing so gives us 3(5) + 4(2) - 5(2) = 15 + 8 - 10 = boxed{13}. The answer is: 13

answer:The school needs to cover 50 devices. The 40 software package covers 5 devices, so the school would need 50/5 = 10 packages of this software. 10 packages of the 40 software would cost 10 x 40 = 400. The 60 software package covers 10 devices, so the school would need 50/10 = 5 packages of this software. 5 packages of the 60 software would cost 5 x 60 = 300. By buying the 60 software package instead of the 40 software package, the school can save 400 - 300 = 100. 100 The answer is: 100

answer:Madeline has x and her brother has half as much, which means her brother has x/2. The total amount of money they have together is the sum of what Madeline has and what her brother has: x + x/2 = 3x/2. We are given that the total amount of money they have together is 72, so we can write: 3x/2 = 72. Multiplying both sides by 2/3, we get: x = 48. The value of x is 48. 48 The answer is: 48