Should be C.
As we need info required in both 1(we know the sales made if we know yesterday's amount) & 2 (gives total sales made yesterday, hence the amount too).

IS it [color=white]C[/color]?

cans wrote:A certain salesman earns a flat payment of $12 per sale on sales up to his daily quota of 10 sales.iF the salesman earns a flat payment of $16 per sale on sale in excess of 10 sales, how many sales did the salesman make today?

1.The salesman earned $48 more for sales made today than for sales made yesterday.
2.yesterday the salesman made 10 sales.

y-> yesterday;
t-> today;

1)t-y=$48;
as here no information is given about t and y, so both t and y can assume different values for example t=48,y=0; t=168; y=120; hence 1 alone is insufficient to answer the question.

2) y=10*12; as no relationship is given between t and y; hence 2 alone is also not sufficient to answer the question;

combining 1 and 2 we have;
t-120=48;
t=10*12+3*16;
i.e. for 10 sales made today he earns 10*12=120$ and for extra 3 sales he made 3*16=48$ hence total no. of sales made today are 13;

therefore answer should be C

IMO C

cans wrote:A certain salesman earns a flat payment of $12 per sale on sales up to his daily quota of 10 sales.iF the salesman earns a flat payment of $16 per sale on sale in excess of 10 sales, how many sales did the salesman make today?

1.The salesman earned $48 more for sales made today than for sales made yesterday.
2.yesterday the salesman made 10 sales.

IMO C..
1.Data insufficient as we dont know the sales made yesterday.
2.Data insufficient as we dont know the relation between yesterday s sale and today s sale
but together the data is sufficient

+1 for C.