The altitude of Death Valley, California, is 282 feet below sea level. A hot air balloon is launched from the bottom of Death Valley and rises at a rate of 10 feet per second. After 12 seconds, the balloon captain lowers the balloon 15 feet. What is the altitude of the hot air balloon after being lowered?

The altitude is 177 feet below sea level after being lowered.

The balloon rises 120 feet after 12 seconds and then is dropped 15 feet. So 120 - 15 = 105. And 282 - 105 = 177

38+105= 143, 39+104=143, and you will find then adding the numbers on opposite sides, moving inwards yields the answer 138 every time. because of this, you’re going to multiply 138 times the number of pairs, which is 34. therefore, 34*138= 4692(i’m sorry if it’s the wrong numbers, but it’s the right concept)