D = r t
384 = 640 * t
384/640 = t
.6 = t .6 of an hour
.6 hr * 60min/1 hr = 36 minutes (just in case it needs to be in minutes)
Answer:
0
Step-by-step explanation:
Answer:
The mean of the combined group is 76.67 ≈ 77
Step-by-step explanation:
- The sum of the grades in Tom's group is 20×70 = 1400
- The sum of grades in Alice's group is 10×90=900
- The sum of gradees in the combined group is =1400+900=2300
- Then the mean grade of the combined group is

where
- 2300 is the sum of the all grades in the combined group
- 30 is the total number of people in the group
Answer:
1.75
c
+
2.25
a
=
1083.00
now we still know, that
a
=
508
−
c
so we can substitute it into the second formula
1.75
c
+
2.25
(
508
−
c
)
=
1083
now its just simple algebra
1.75
c
+
1143
−
2.25
c
=
1083
60
=
0.5
c
so:
c
=
120
Step-by-step explanation: