A construction crew is lengthening a road that originally measured 47 miles. The crew is adding one mile to the road each day. Let L be the length (in miles) after D days of construction. Write an equation relating L to D. Then use this equation to find the length of the road after 31 days.

78 miles

Step-by-step explanation:

Given that:

Original length, L = 47 miles

Additional length (miles) added per day, = 1 mile

Representing as an equation :

L(D) = original length + additional length per day * number of days

Let, D = number of days

L(D) = 47 + D

Length after 31 days :

L(31) = 47 + 31

= 78 miles

answer: first option i.e. 'a' is correct.

step-by-step explanation:

since we have given that

number of minutes to wrap a small gift box = 4 minutes

we need to find the number of gifts to be wrapped in 5 minutes

since there is a direct variation, as the number of minutes will increase with   number of gifts to be wrapped.

so, let the number of gifts to be wrapped in 5 minutes be x.

so, it becomes,

hence, first option 'a'   is correct.