Help really needed. Thank you so much

Question

Oil is delivered to a refinery between the hours of midnight (t = 0) and 5 a.m. (t = 5). Selected values of the rate of delivery are shown in the table below, with t measured in hours past midnight, and R(t) measured in gallons per hour. Use 4 trapezoids to estimate the total amount of oil to the nearest gallon that is delivered between midnight and 5 a.m

t(hours)	0	1	2	4	5
R(t) gals/hour	100	250	200	350	100

Answer 1

The area of a trapezoid is b(h1 + h2)/2

The sum of the areas of the four trapezoids is (100+250)/2 + (250+200)/2 + (200+350) + (350+100)/2

= 175 + 225 + 550 + 225 = 1175 gallons