Đỗ Phi Phi
26/07/2017 at 23:12Alex placed 9 number cards and 8 addition symbol cards on the table as shown.
| 9 | + | 8 | + | 7 | + | 6 | + | 5 | + | 4 | + | 3 | + | 2 | + | 1 |
Keeping the cards in the same order he decided to remove one of the addition cards to form a 2-digit number. If his new total was 99, which 2-digit number did he form?
A.32 B.43 C.54 D.65 E.76
-
The total of the cards are: \(9+8+7+6+5+4+3+2+1=45\)
The total of the cards that can removed 1 card is: \(\left(45-1\right)to\left(45-9\right)\)
From this operation and the question, we see only \(C.54\) satisfy these.
So the answer is C
Selected by MathYouLike -
FA KAKALOTS 08/02/2018 at 22:04The total of the cards are: 9+8+7+6+5+4+3+2+1=45
The total of the cards that can removed 1 card is: (45−1)to(45−9)
From this operation and the question, we see only C.54
satisfy these.
So the answer is C
-
Duy Trần Đức 11/02/2018 at 08:30The total of the cards are: 9+8+7+6+5+4+3+2+1=459+8+7+6+5+4+3+2+1=45
The total of the cards that can removed 1 card is: (45−1)to(45−9)(45−1)to(45−9)
From this operation and the question, we see only C.54C.54 satisfy these.
So the answer is C
