Michael wants to buy a new 4K HD TV. The cheapest TV is advertised as $1100$1100. He has saved $300$300 already and has a part-time job earning $160$160 per week. How many weeks will it take before he has saved up enough to buy the cheapest TV?
Since Michael needs to save up at least $1100$1100 to buy the TV, he must keep earning $160$160 per week until he has greater than or equal to$1100$1100.
Hence, the inequality can be written as:
300+160n300+160n
≥≥
11001100
Next, make sure that only nn is on the left side
300+160n300+160n
≥≥
11001100
300+160n300+160n-300−300
≥≥
11001100-300−300
Subtract 300300 from both sides
160n160n÷160÷160
≥≥
800800÷160÷160
Divide both sides by 160160
nn
≥≥
55
n≥5n≥5
Question 2 of 5
2. Question
A hard drive holds about 7575 hours of movie videos. So far it has 5252 hours. You estimate that each movie is 22 hours long. How many movies can we transfer on top of the movies that are already in the hard drive?
Hours already on hard drive=52Hours already on hard drive=52
Number of hours per movie=2Number of hours per movie=2
Number of movies=nNumber of movies=n
First, form an inequality from the problem
Since the hard drive only has a capacity of 7575 hours, the total number of 2 hour movies to be added on top of the 52 hours worth that is already on the hard drive must be less than or equal to75.
Hence, the inequality can be written as:
52+2n
≤
75
Next, make sure that only n is on the left side
52+2n
≤
75
52+2n-52
≤
75-52
Subtract 52 from both sides
2n÷2
≤
23÷2
Divide both sides by 2
n
≤
11.5
Since we can only add a whole movie and we cannot go over 75, we need to round down the answer to n≤11
n≤11
Question 3 of 5
3. Question
James currently weighs 108 kg. He wants to weigh less than 90 kg. If he can lose an average of 112 kg per week through exercise and diet, how long will it take to reach his goal?
Since James wants to weigh less than 90 kg, he must keep losing 112 every week until he weighs less than90 kg.
Hence, the inequality can be written as:
108-112n
<
90
Next, make sure that only n is on the left side
108-112n
<
90
108-112n-108
<
90-108
Subtract 108 from both sides
-112n÷(-112)
<
-18÷(-112)
Divide both sides by -112
n
>
12
Flip the inequality
n>12
Question 4 of 5
4. Question
A medium-sized bag of potatoes weighs 1 kg more than a small bag. A large bag weighs 4 kg more than a small bag. If the total weight is at most 14 kg, what is the most that a small bag could weigh?
The total weight of the three bags must be less than or equal to14 kg.
Hence, the inequality can be written as:
S+M+L
≤
14
Next, make sure that only n is on the left side
S+M+L
≤
14
s+s+1+s+4
≤
14
Substitute the known values
3s+5
≤
14
Combine like terms
3s+5-5
≤
14-5
Subtract 5 from both sides
3s÷3
≤
9÷3
Divide both sides by 3
s
≤
3
s≤3
Question 5 of 5
5. Question
Jack is flying an air balloon at an altitude of 16000 feet and is experiencing some bad weather. For him to fly safely, Jack needs to increase his altitude to at least 17000 feet or decrease his altitude to no more than 13000 feet. Form an inequality.