Going upstream: 432 km / 6 hours = 72 km/h
Going downstream: 384 km / 4 hours = 96 km/h
Going upstream against the current means that the effective speed is:
r_boat - r_current = 72
Meanwhile, going downstream with the current means;
r_boat + r_current = 96
Adding both equations (to cancel out r_current) gives:
2r_boat = 72 + 96
r_boat = 84 km/h
Substituting back into one of the original equations: r_current = 12 km/h.
Answer:
x = 25
Step-by-step explanation:
<em>Step 1: Identify the similar triangles</em>
Triangle DQC and triangle DBR are similar
<em>Step 2: Identify the parallel lines</em>
QC is parallel to BR
<em>Step 3: Find x</em>
DQ/QB = DC/CR
40/24 = x/15
x = 25
!!
27) if a = 1/a
multiply both sides by a
a * a = 1/a * a
a^ 2 = 1
Answer is D) 1
28)
6 x 75 = 450
7 x 80 = 560
8 x 85 = 680
9 x 90 = 810
Total all students in class = 6 + 7 + 8 + 9 = 30 students
Total score of whole class:
450 + 560 + 680 + 810 = 2500
Average = 2500 /30 = 83.3 = 83 1/3
Answer is C) 83 1/3
We need more info like a) this b) or this stuff like that
Answer:
Step-by-step explanation:
Density = mass/volume.
Therefore.
2.7g/cc = x/15cc
x = 2.7x 15
x = 40.5g.
