Afalling object travels a distance given by the formula
d = 5t + 16t2,
where t is measured in seconds and d is measured in feet. how long will it take for the object to travel 21 ft?

The time taken by object to travel 21 ft is 1 sec

Step-by-step explanation:

The distance travel by falling object given as

d = 5 t + 16 t²

The Distance cover by object to travel = 21 ft

so , from Distance time equation

21 = 5 t + 16 t²  

or, 16 t² + 5 t - 21 = 0

Or, 16 t² - 16 t +21 t - 21 = 0

Or, 16 t ( t - 1) + 21 (t - 1) = 0

Or.   (t - 1) (16 t + 21) = 0

Or,  (t - 1) = 0   And   (16 t + 21) = 0

∴      t = 1         And   t = (    )

Hence The time taken by object to travel 21 ft is 1 sec Answer

since proposition states that a number is greater than 25, if is true then the number must actually be greater than 25.

this implies that all possible options, except 24, can be accepted