Solve using elimination method

Germaine walks at the rate of 10 feet every five seconds while nolan walks at the rate of 15 feet every five seconds. if germaine has a head start of 25 feet, how many seconds will they be at the same spot?

The square pyramid has a volume of 441 cubic inches. what is the value of x? 1/7x is the height x is the base

Look at the figure below: triangle abc is a right triangle with angle abc equal to 90 degrees. the length of ac is 5 units and the length of ab is 4 units. d is a point above c. triangle adc is a right triangle with angle dac equal to 90 degrees and dc parallel to ab. what is the length, in units, of segment cd?