Three liquids P, Q

PHYSICS · Subjective · A Level · Physics · Further mechanics and thermal physics · Further mechanics and thermal physics

Problem

Three liquids P, Q, and R are given.

4\ \mathrm{kg}

of P at

60\ ^\circ\mathrm{C}

and

1\ \mathrm{kg}

of R at

50\ ^\circ\mathrm{C}

, when mixed, produce a resultant temperature of

55\ ^\circ\mathrm{C}

. A mixture of

1\ \mathrm{kg}

of P at

60\ ^\circ\mathrm{C}

and

1\ \mathrm{kg}

of Q at

50\ ^\circ\mathrm{C}

has a temperature of

55\ ^\circ\mathrm{C}

. What is the resulting temperature when

1\ \mathrm{kg}

of Q at

60\ ^\circ\mathrm{C}

is mixed with

1\ \mathrm{kg}

of R at

50\ ^\circ\mathrm{C}