In a triathlon, jenny swam for 1 hour, biked for 1.75 hours, and ran for 1 hour. her average biking speed was 2 times her average running speed, and her average running speed was 8 times her average swimming speed. the total distance of the triathlon was 55.5 kilometers. write and solve a linear equation to calculate jenny’s average swimming speed (x) in kilometers per hour. give your answer to the nearest tenth. asap 30 points

28r + 8r + r = 55

Step-by-step explanation:

Some values you know (given or calculated) and some things you do not know.

             RATE         TIME         DISTANCE

BIKE          2*8r         1.75

RUN           8r

SWIM           r            1

Total                                     55

Give a variable to unknown running speed and fill in everything.

             RATE         TIME         DISTANCE

BIKE          16r         1.75           28r        

RUN           8r            t            8rt

SWIM           r            1             r

Total                                     55

Notice some trouble? WHY? I missed seeing the "ran for one hour". the variable t is KNOWN! This will be corrected here:

             RATE         TIME         DISTANCE

BIKE          16r         1.75           28r        

RUN           8r            1            8r

SWIM           r            1             r

Total                                     55

Calculations used to fill out the graph:

Then her running speed was 8r,

and her biking speed was 2*(8r) = 16r.

Swimming for 1    hour, Jenny covered the distance of 1*r = r kilometers.

Biking   for 1.75 hour, Jenny covered the distance of 1.75*16r = 28r kilometers.

Running  for 1    hour, Jenny covered the distance of 1*2r = 8r kilometers.

Everything is filled and looks good. There is a sum of distances in just the one single variable, r.

Solve for r, and this is the swimming speed.

28r + 8r + r = 55

answer 1 : option "c"

answer 2 : option "d"

answer 3 : option "b"

answer 4 : option "d"

answer 5 : option "b"

answer 6 : option "a"

answer 7 : option "c"

answer 8 : option "d"

answer 9 : option "c"

answer 10 : option "d"

answer 11 : option "c"

answer 12 option "b"

answer 13 option "c"

answer 14 option "c"

answer 15 option "d"

answer 16 option "a"

answer 17 option "b"

answer 18 option "c"

answer 19 option "a"

answer 20 option "a"

answer 21 option "c"

d