ElectricPavlov

Distance   d        original rate   r       t = 5

d/r = 5         3/4 of the way is 3.75 hr    1.25 hr to go

                                                               gets delayed 1.5 hr for engine trouble

                                                                  speeds up 10  and only arrives 1.25 late

                                                                      so instead of 1.25 hr to finish ....when he speeds up

                                                                         it only takes him 1 hour to finish the last 1/4 d

1/4 d /(r+10 ) = 1 hour

r = d/5

1/4 d / ( d/5+10)  = 1

1/4 d = d/5 + 10

d = 200 km

18:225      divide both sides by 18

1:13

I = V/ R  

This question has been asked several times before....

Voltage is applied 'across' the wire  (not through it)  and a current of .2 amps passes 'through' it

.2 = 50 / R      Solve for R = 250 ohms

Now cut the wire in half.....this will cut the resistance in half   to 125 ohms

   and increase the Voltage to 300

Now the current becomes   I = V/R =  300 / 125 = 2.4 amps   (2400 mAmps)

Edited....  THANX for finding my error , Alan !

9t + h = 93

4t + h = 43         multiply this equation by  -2.25  and add it to the first equation

-9t-2.25h = -97             (we are trying to 'eliminate' the 't' then  solve for 'h')

-1.25 h = -4

h = L 3

Now yo can use this value of 'h' in one of the equations to solve for 't'  ........

10 pound mixture

c = cashews               cost   6.50 c

p = peanuts = 10-c     cost =  4.00p(10-c)          summed =  10 (4.75)

6.5 c + 4(10-c) = 10 (4.75 )    

                  solve for 'c' the pounds of cashews, then  pounds of peanuts = 10-c

  Area of a triangle = 1/2 b * h    b = base  h = height

base is   6.4 + 6.4 in this example

Find the height (the dotted line) using the Pythagorean theorem

6.4^2 + h^2 = 9^2

h^2 = 9^2  -  6.4^2   

  solve for 'h'  then use the red equation above to find the area   

90 passengers

r = # regular                         revenue from =  121r

s = #sleeper = (90-r)            revenue from =  285 (90-r)      summed , these = 19418

121 r        + 285 (90-r)      = 19418     solve for 'r' the # regular    then # sleeper = 90-r

Find the hypotenuse of the right triangles via pythagorean theorem...

a^2 + (1/2b)^2 = hyp^2

44   +   289      = hyp^2

hyp = 18.248

perimeter =  hyp + hyp + b = ..........

A/B  = a/8

B/C= 12/c

A/B * B/C    =   a/8 * 12/c

A/C = 12a/8c    =   2/1

      soooo   12a = 16c

                     a/c  = 16/12  =   4/3

choices  5 6 7 8 9

position 1    5 choices

position 2    5 choices

position 3    5 choices

position 4    5 choices

5 x 5 x 5 x 5 = 625 possible numbers      EVEN numbers end in 6 or 8  ( 2 out of 5 choices)

                        2/5 x 625 = 250 evens