ElectricPavlov

IF you meant the roof is  '10 meters square'

then the # square meters of the roof are 10 mx 10 m= 100 m^2

10.72 tile/m^2 x 100 m^2 = 1075 tiles

Starts out 17 inches tall   y intercept = b = 17

each hour burns (15-17)/2 = -1 in/hr  = m = slope

at t= 0 the candle would have been

17 + 3(1) = 20 inches tall at t= 0 when it was lit = b = h intercept

h = -t + 20            when t = 5     height (y) = 15 inches    Check!

in 8 hours   h = -8+20 = 12 inches tall

= 8 x3 /2    x 10 ^(7+6-4) = 12 x 10^9

(4/3)*pi*5^3 = v = 523.599    (units cubed)

See other identical post.

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800000 - 400000 = 400000 left after cash payment

400, 000 (1+.04)^4 = 467943.42 at the end of 4 years

467943.42 - 120,000 = 347943.42 ('new' loan amount)

347943.42 (1+.04)^2 = 376335.60   at year end 6

   - 80 000 payment = 296335.60

296335.60 x (1.04)^1 = final payment = $ 308,189.03

2 KI  + Pb(NO3)2  -------> 2 K NO3  + Pb I2      Is the balanced equation......

KI mole weight is 39.0983 +126.90 = 165.9983 gm

From the equation    TWO moles of KI will result in ONE mole PbI2

Pb(NO3)2  mole weight = 331.208 gm  ( and  2 KI = 331.9966 gm  (so I will assume this is a stoichiometric rxn))

1.25 g of KI represents   1.25/165.9983 = .00753 mole

   One-half of this will be the number of moles of Pb I2 produced

PbI2 mole wt = 207.2 + 2(126.9) = 461 gm

1/2 * .00753 mole  *  461 gm/mole = 1.7357 gm of PbI2

(edited)

When it is stationary, v = 0

If we take the derivative of the displacement fxn , it is the velocity function

   then we can set the VELOCITY function = 0 to find TIME to substitute in to the DISPLACEMENT fxn

the derivative is

    6t-12 = velocity

    6t-12 = 0   yields t = 2 sec

Substitute this in to the displacement fxn

3(2^2) -12(2) +15 = 3 m

Maybe.....ya have more info?