CPhill

P  = (1/3) ( 2/4)   = 2/12  = 1/6

Original Price [1 - .36]  = $32    divide both sides by  [ 1 - .36] 

Original Price  = 32  / [ 1 - .36 ] =   $50

I'm assuming that the water surface is 30m below the top of the well......so

-30  = -4.9t^2     divide both sides by -4.9

[ -30 / -4.9 ]  = t^2     take the positive root of both sdes

sqrt [ -30 / -4.9]  = t   ≈ 2.47 sec

Original Price + .07 * Original Price  =  105.93

Original Price (1 + .07)  =  105.93      divide both sides by ( 1 + .07)

Original Price  = 105.93 / (1 + .07)   =   $ 99.00

4.9(1.8)^2  = 15.876 m  = 15.976(39.37)/(12)  = 52.414 ft

35x  = 51y   rearrange as

x / y   =  51 / 34

Let x be the number of $10 bills

(7/4)x  = $20 bills

8x   = $50 bills

So value * times nmber  = total amount

10x + 20 (7/4)x + 50(8x) = 1780

10x + 35x + 400x  = 1780

445x  = 1780  divide by 445

x = 4  = $10 bills

(7/4)x  = (7/4)(4) = 7  = $20 bills

8(4)  = 32  = $50 bills

I like the trig approach, heureka......!!!!!

2(19)^1 + 4(19)^0  =

38 + 4  =

42  ....!!!!

[-6 - 2 ] * 5   / 4  =

[ - 8 ] * 5   / 4   =

- 40  / 4   =

-10

-6 * 5  +  4 * 2  =

-30 + 8  =

-22