Speed=distance / time; ⇒distance=speed * time
Distance traveled by Ricardo
Distance (Ricardo)= (3 ft / s) * 15s+3 ft/s * time=45 ft+3 ft/s*t=45+3t
Distance traveled by John:
Distance(John)=(4 ft/s) * time=4t
Distance traveled by Ricardo=Distance traveled by John
3t+45=4t
Answer: D. 3t+45=4t
Volume of the pyramid:
V = 1/3 · B · h
B = 8 ft²
tan 30° = height / 7√3
1/√3 = height / 7√3
height = 7 ft
V = 1/3 · 8 · 7 = 18.67 ft³ ≈ 19 ft³
Answer : D ) 19 ft³
I don't know if this is the answer that you are looking for, but would the answer be all solutions?
You need to go from slope-intercept (

) to standard form (

).
slope-intercept form of your provided values:
now, solve for x and y
Your answer is 
.
H=(√3)*a/2 = 41.2
So, a=2*41.2/√3=47.6