Asked: If a certain tree reached a height of 78 inches by the end of 2023, did it grow by less than 15 inches that year?
(1) By the end of 2023, the tree was less than 30 percent higher than by the end of 2022.Let the tree reached a height of x inches by the end of 2022.
1.3x > 78
x > 78/1.3 = 60; x > 60 inches
The tree grew that year = 78-x < 78-60 = 18 inches
If x = 61; The tree grew that year = 78-x = 78-61 = 17 inches > 15 inches
If x = 65; The tree grew that year = 78-x = 78-65 = 13 inches < 15 inches
NOT SUFFICIENT
(2) In 2023, the tree grew by more than 20 percent of its height by the end of 2022.Let the tree reached a height of x inches by the end of 2022.
1.2x < 78
x < 78/1.2 = 65 inches
The tree grew that year = 78-x > 78-65 = 13 inches
If x = 64; The tree grew that year = 78-x = 78-64 = 14 inches < 15 inches
If x = 61; The tree grew that year = 78-x = 78-61 = 17 inches > 15 inches
NOT SUFFICIENT
(1) + (2)
(1) By the end of 2023, the tree was less than 30 percent higher than by the end of 2022.Let the tree reached a height of x inches by the end of 2022.
1.3x > 78
x > 78/1.3 = 60; x > 60 inches
(2) In 2023, the tree grew by more than 20 percent of its height by the end of 2022.1.2x < 78
x < 78/1.2 = 65 inches
60<x<65;
If x = 64; The tree grew that year = 78-x = 78-64 = 14 inches < 15 inches
If x = 61; The tree grew that year = 78-x = 78-61 = 17 inches > 15 inches
NOT SUFFICIENT
IMO E