All of the following are possible sources of error in a scientific investigation except

Ian has 20 football cards, and Jason has 44 baseball cards. They agree to trade such that jason gives Ian 2 baseball cards for every card Ian gives to Jason. After how many such trades will Ian and Jason each have an equal number of cards?

Mom paid $2.40 for a 3/4 pound of cereal, how much is that per pound

A four pound duck, initially at a temperature of 50 degrees is place in an oven preheated to 375 degrees at 1:00. At 2:15 the duck has reached an internal temperature of 125 degrees. When will it reach 175 degrees.

If julie earns $33.75 for 3 hours write the constant of proportionality for this direct variation

What would be the x-intercept and y-intercept of the equation 2x+3y=3?

At sunset, the temperature was 4 degrees. Then at sunrise the next morning, it was - 7 degrees. What is the difference between these temperatures?

How many possible sandwiches: 4 types of bread & 6 types of cold cuts?

What is the probability of choosing an ace or a black card? 6/13 7/13 8/13

Whats 21/8 as a mixed number

You bought a freezer that is 2 feet wide, 4 feet long and 30 inches deep