Answer:
9 mph
Step-by-step explanation:
-let x be the speed of current and t be time. The speed equation for both directions can then be represented as:

#Since t is equal in both, we can do away with t.
#We the divide the downstream equation by the upstream equation as:

Hence, the boat's speed in still water is 9 mph
Answer:
a = 60
b = 90
c = 150
Step-by-step explanation:
Numerele a, b și c sunt direct proporționale cu 2, 3 și 5.
Unde k este constantă de proporționalitate
a ∝ 2
a = 2k
b ∝ 3
b = 3k
c ∝ 5
c = 5k
Dacă media aritmetică a celor trei numere este egală cu 100, determinați numerele a, b și c
= 2k + 3k + 5k / 3 = 100
= 10k / 3 = 100
Cross Multiply
= 10k = 3 × 100
= 10k = 300
Împărțiți ambele părți la 10
k = 300/10
k = 30
Pentru numărul a
a = 2k
a = 2 × 30
a = 60
Pentru numărul b
b = 3k
b = 3 × 30
b = 90
Pentru numărul c
c = 5k
c = 5 × 30
c = 150
Prin urmare, a = 60, b = 90, c = 150
A scale drawing is an enlarged or reduced drawing of an object that is similar to an actual object. Maps and floor plans are smaller than the actual size. A scale drawing of a human cell is larger than the actual size.
On a map, the equal sign in 1 in. = 30 mi does not mean that the two quantities are equal, as it would in an equation.
A scale is the ratio that compares a length in a drawing to the corresponding length in the actual object. If a 30-mile road is 1 in. long on a map, you can write the scale of the map in these three ways:
Go here for more. http://www.phschool.com/itext/mgmath_course2/Ch05/05-07/PH_MSM2_ch05-07_Obj1.html
It is 43 I used calculator