Question

Two taps supply water to a container, one at the temperature of $20^{\circ }C$ at the rate of $2$kg/minute and another at $80^{\circ }C$ at the rate of $1$ kg/minute. If the container gets water from the two taps simultaneously for $10$ minutes, then the temperature of water in the container is

• A. $35^{\circ }C$
• B. $30^{\circ }C$
• C. $50^{\circ }C$
• D. $40^{\circ }C$
• E. $45^{\circ }C$

Answer 1

Answer: (D)

Mass of water collected from tap $1cm10$ minutes,
$m_1=2\times 10=20kg$
$T_1=20^{\circ }C$
Mass of water collected from tap $2cm10$ minutes
$m_2=1\times 10=10kg$
$T_2=80^{\circ }C$
Final temperature
$T=\frac{M_1{T}_1+M_2{T}_2}{M_1+M_2}$
$=\frac{20\times 20+10\times 80}{30}=40^{\circ }C$