Answer:
Step-by-step explanation:
Remark
Very interesting question. If she had 7 cards left, she drew out 43. She must draw them out with no break in the sequence. So it goes 1,2,3 ... 30,31,32 ... 40,41,42,43
The cards can be drawn in any order but you must wind up with 1 ... 43 by the time you are done.
Givens
a_1 =1
a_43 =43
n = 43
Formula
Sum = (a_1 + a_43)*n/2
Solution
Sum = (1 + 43)*43/2
Sum = (44 )* 43 /2
Sum = 22 * 43
Sum= 946
