A tap supplies water at 25oC while another supplies water at 75oC. If a man wishes to bathe with water at 40oC, the ratio of the mass of cold water to the mass of hot water required is
A
1 : 3
B
15 : 8
C
7 : 3
D
3 : 1
Verified Correct Answer: C.
Physical Principles & Numerical Solution
Heat lost = heat gained
mh x c x (75 - 40) = mc x c x (40 - 25)
\(\frac{m_h}{m_c}\) = \(\frac{35}{15}\)
= \(\frac{7}{3}\)
Source: Myschool Past Questions Archive (Record #28376)