23. Which expression defines the given series for seven terms? -4 + (-5) + (-6) +...
Σ»-3)
Σ--1)
-η - 3)
Σ(3-1)

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?

In parallelogram abcd the ratio of ab to bcis 5: 3. if the perimeter of abcd is 32 find ab

Jenisey has $24 to spend on seven pencils. after buying them she had $10. how much did each pencil cost.?