[Video] Q8: Ken is working this summer as part of a crew on a farm. he earned $8 per hour for the first 10 hours he worked this week. because of his performance, his crew leader raised his salary to $10 per hour for the rest of the week. ken saves 90% of his earnings from each week. what is the least number of hours he must work the rest of the week to save at least $270 for the week?

Explanation for Question 8 From the Math (No Calc) Section on the Official Sat Practice Test 7

Question eight says Ken is working this summer as part of a crew on 2 a farm. He earned $8 per hour for the first 10 hours. 3 He worked this week because of his performance. 4 His crew leader raised his salary to $10 per hour for the rest of 5 the week can say 90% of his earnings from each week. 6 What is the least number of hours? He must work the rest of the 7 week to earn at least $270 for the week. 8 So we know that he's already earned $80 because he earned $8 per hour 9 for the first 10 hours. So eight times 10 is 80. 10 We know he's starting off with $80. 11 And then for the next X amount of hours that he works, 12 he's going to make $10 per hour. 13 And we're going to represent that as 10 X. 14 We also know that he only saves 90% of his artists, 15 which means that we're going to have to multiply this by 0.9 to figure 16 out how much of this he's actually saving. And finally, 17 this all must be greater than or equal to 270, 18 because we're trying to find the lowest value of X that would be greater 19 than or equal to 270. 20 So now I just need to solve for X. I'm just going to rewrite 21 this as 10 times. 22 Uh, eight plus X times 0.9 is greater than or equal 23 to 70 greater than or equal than two 17, 24 because I know that 10 times not times 0.9 is just nine and that 25 makes it easier to do this math quickly. 26 Then I'm going to factor, or I'm going to divide both sides by nine 27 to get eight plus acts is less than or equal to 30. 28 And finally I'm going to subtract eight from both sides. 29 And that gives me the ax is greater than or equal to 22, 30 which means that the least number of hours that he can work for the 31 rest of the week and still earn $270 for the week is 22 32 hours or answer choices.