P,Q and R together earn Rs.1620 in 9 days. P and R can earn Rs.600 in 5 days. Q and R in 7 days can earn Rs.910. How much amount does R can earn per day?  Choose the correct choice from the following answers.
A) Rs.40	B) Rs.70	C) Rs.90	D) Rs.100	E) Rs.120
Explanation :   Amount Earned by P,Q and R in 1 day = 1620/9= 
<gadget id="calculator">1620/9</gadget>
<output>180</output>
180 ---(1)   Amount Earned by P and R in 1 day= 600/5= 
<gadget id="calculator">600/5</gadget>
<output>120</output>
120	---(2)   Amount Earned by Q and R in 1 day= 910/7= 
<gadget id="calculator">910/7</gadget>
<output>130</output>
130	---(3)   (2)+(3)-(1)=&gt; Amount Earned by P , Q and 2R in 1 day   - Amount Earned by P,Q and R in 1 day = 120+130-180= 
<gadget id="calculator">120+130-180</gadget>
<output>70</output>
70=&gt;Amount Earned by R in 1 day = 70   Answer : Option Rs.70
<result>B</result>
P,Q and R together earn Rs.1620 in 9 days. P and R can earn Rs.600 in 5 days. Q and R in 7 days can earn Rs.910. How much amount does R can earn per day?