Lester’s first draft of his English paper had 1,644 words. After revising his paper, Lester’s second draft had 25% fewer words. How many words did Lester’s second draft of his English paper have?

What's the difference between: x≥0 and nonnegative integer. ?

Aswimming pool has an input pump for filling the pool and an output pump for emptying the pool. the input pump can fill the pool in 3 hours, and the output pump can drain the pool in 5 hours. as you go to bed, the pool is full, but a neighbor’s kid turns on the output pump. at midnight, you awake to find the pool half empty. immediately, you turn on the input pump, but you are sleepy and forget to turn off the output pump. at what time will the pool become full?

What is the solution to the equation? k/6.4=8.7 2.3 5.568 15.1 55.68