The LD (subscript 50) for a drug dose that would be fatal for 50% of the population. The LD (subscript 50)for aspirin in rats is 1.75 grams/kilogram of body weight. Calculate how many aspirin tablets a human weighing 155 pounds would have to take to reach this dosage. (1 aspirin = 5 grams = 325 mg)

It isn't clear in the problem that this is 1.75 g aspirin tablet/kg or 1.75 g active ingredient/kg.

I assume the problem means 1.75 g of active ingredient/kg body weight.
Convert 155 g body weight to kg. That will be 155 pounds x (2.2 kg/1 pound)= ?kg
Then kg body weight x (1 tablet/0.32g) = x tablets.

To calculate the number of aspirin tablets a human weighing 155 pounds would have to take to reach the LD50 dosage, we need to convert the weight from pounds to kilograms and then use the given LD50 value for rats.

Let's first convert the weight of the person from pounds to kilograms. We know that 1 pound is approximately equal to 0.4536 kilograms.
So, 155 pounds is equivalent to 155 × 0.4536 = 70.31 kilograms (rounded to two decimal places).

Next, we use the LD50 value for rats, which is 1.75 grams/kilogram of body weight.

To find the dosage in grams for a 70.31-kilogram human, we multiply the weight by the LD50 value:
70.31 kilograms × 1.75 grams/kilogram = 122.77 grams (rounded to two decimal places).

Now, we know that 1 aspirin tablet is equal to 325 mg or 0.325 grams.

To calculate the number of aspirin tablets needed to reach the LD50 dosage, we divide the dosage in grams by the weight of one tablet:
122.77 grams ÷ 0.325 grams/tablet = 377.88 tablets (rounded to the nearest whole number).

Therefore, a human weighing 155 pounds would need to take approximately 378 aspirin tablets to reach the LD50 dosage for rats.