Final answer:
When the tire size on a Ford F150 is changed without updating the onboard computer, the speedometer will no longer accurately display the speed of the truck. The actual speed can be determined by using the ratio of the new tire diameter to the old tire diameter. If the speedometer reads 65 mph with the new 28.2 inch tires, the truck is actually traveling at approximately 71.2 mph. If 24 inch tires are used instead, the actual speed would be approximately 61.7 mph when the speedometer reads 65 mph.
Step-by-step explanation:
When the standard 25.7 inch tires on a Ford F150 are replaced with 28.2 inch tires without updating the onboard computer, the speedometer will no longer accurately display the speed of the truck. The actual speed will be higher than what is shown on the speedometer. To determine the actual speed, you can use the ratio of the new tire diameter to the old tire diameter. In this case, the ratio is 28.2/25.7 = 1.097. If the speedometer reads 65 mph, you would multiply it by the ratio to find the actual speed: 65 mph x 1.097 = 71.2 mph. Therefore, the truck was actually traveling at approximately 71.2 mph.
If 24 inch tires were used instead, you would calculate the ratio as 24/25.7 = 0.934. When the speedometer reads 65 mph, you would multiply it by the ratio to find the actual speed: 65 mph x 0.934 = 61.7 mph. Therefore, the truck would have been actually traveling at approximately 61.7 mph if 24 inch tires were used and the speedometer read 65 mph.