The answer is A but can someone explain why with the math typed out ? David has five lawns to mow on Monday.
The first lawn is 20 ft by 30 ft. The second lawn
is 200 ft by 45 ft. The third yard is 50 ft by 50 ft.
The fourth yard is 90 ft by 60 ft. The fifth yard
is 150 ft by 95 ft. He can mow 240 ft severy
minute.
Approximately how long will it take him to mow all five lawns?
A. 2 hours and 12 minutes
B. 2 hours and 20 minutes
C. 1 hour and 9 minutes
D. 6 hours and 58 minutes

Parabolas y=−2x^2 and y=2x^2+k intersect at points a and b that are in the third and the fourth quadrants respectively. find k if length of the segment ab is 5.

Submarines control how much they float or sink in the ocean by changing the volume of air and water contained in large ballast tanks. when the tanks are completely full of water, the submarine increases its overall mass and sinks down to the bottom. when the tanks are completely full of air, the submarine reduces its overall mass and floats to the surface. depending on the density of the seawater surrounding the submarine, it will pump seawater in or out of the tanks in order to achieve the same overall density as the sea water and float neutrally in the water. the volume of the submarine never changes. when the tanks are completely full of water, a submarine with a volume of 7.8\times10^3\text{ m}^37.8×10 3 m 3 7, point, 8, times, 10, start superscript, 3, end superscript, space, m, start superscript, 3, end superscript has a total mass of 8\times10^6\text{ kg}8×10 6 kg8, times, 10, start superscript, 6, end superscript, space, k, g. the density of the seawater is 10^3\text{ kg/m}^310 3 kg/m 3 10, start superscript, 3, end superscript, space, k, g, slash, m, start superscript, 3, end superscript. to make that submarine float neutrally, and neither float nor sink in the ocean, what volume of water does that submarine need to subtract from its tanks?

3c2 + 2d)(–5c2 + d) select all of the partial products for the multiplication problem above.