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?

Foaltohors Aug 6, 2021

#1**+1 **

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.

Guest Aug 6, 2021

#2**0 **

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

ElectricPavlov Aug 6, 2021