+65 Dr Malcolm had some syringes on his lab. He used 25% of the syringes in the morning and another 45 syringes in the afternoon. He used the remaining 1/3 of the syringes at night. How many syringes did Dr Malcolm have at first?
If the number of remaining syringes used at night was 1/3 of the number that Dr. Malcolm started with, then the total of the number used during the morning and afternoon was 2/3 of the total.
Let s be the total number of syringes that Dr. Malcolm started with.
Then:
number of syringes used in the morning = 0.25s = s/4
number of syringes used ion the afternoon = 45
And:
s/4 + 45 = 2s/3
Multiply both sides by 12:
3s + 540 = 8s
5s = 540
s = 108
Dr. Malcolm started with 108 syringes.
+34316 25 % is the same as 25/100 = 1/4 th
1/4 x + 45 = 1/3 x
1/12 x = 45
x = 45 * 12 = ________ syringes
