Answer:
20°C
Step-by-step explanation:
Quantity if heat energy supplied is expressed as;
Q = mcΔt
m is the mass = 3kg
Δt is the temperature rise
Q = 5400J
c = 900 J/kg °C
Substitute
5400 = 3(90)Δt
5400 = 270Δt
Δt = 5400/270
Δt = 20°C
Hence the temperature rise is 20°C
Answer: Total Loss or Gain = $0
<u>Step-by-step explanation:</u>
Gain: $55,055 (1 + 0.16)
= $55,055 (1.16)
= $63,863.80
Profit = $8,808.80
Loss: $55,055 (1 - 0.16)
= $55,055 (0.84)
= $46,246.20
Loss = -$8,808.80
Profit + Loss
= $8,808.80 - $8,808.80
= 0
(i) speed = distance / time
so time = distance / speed
here we have
time t = 1080/x hours
(ii) return flight time = 1080 / (x + 30) hours
(a) 1080/x - 1080/(x + 30) = 1/2
Multiplying through by the LCD 2x(x + 30) we get:-
1080*2(x + 30) - 2x*1080 = x(x+30)
2160x + 64800 - 2160x = x^2 + 30x
x^2 + 30x - 64800 = 0
(b) factoring; -64800 = 270 * -240 ans 270-240 = 30 so we have
(x + 270)(x - 240) = 0 so x = 240 ( we ignore the negative -270)
So the speed for outward journey is 240 km/hr
(c) time ffor outward flight = 1080 / 240 = 4 1/2 hours
(d) average speed for whole flight = distance / time
Time for outward journey = 4.5 hours and time for return journey = d / v
= 1080 / (240+30) = 4 hours
Therefore the average speed for whole journey = 2160 / 8.5 = 254.1 km/hr
Combined work problems
job/time + job/time = job/ total time
(1/80) + (1/100) = 1/T
(10/800) + (8/800) = 1/T
18/800 = 1/T
800/18 = T
44.44 hrs = T
Let Tony's age = x
He is 4 years younger than his brother Josh, so Josh's age would be x + 4
He is 2 years older than his sister, so her age would be x - 2
He has a twin, which would be the same age, so the twins age is also x
They all add together to equal 66, so you get:
x + x + x+4 + x-2 = 66
Simplify:
4x +2 = 66
Subtract 2 from both sides:
4x = 64
Divide both sides by 4:
x = 64/4 = 16
Tony is 16 years old.