The half-life a particular radioactive
substance is 10 seconds. If you started
with 100 grams of this substance, how
much of it would remain after 60
seconds?

The price of an item has been reduced by 30%. the original price was $30. what is the price of the item now ?

Define multiplicative inverse. give an example of a number and its multiplicative inverse.

Statements reasons 1. ab ? cd; ad ? bc 1. given 2. ac ? ac 2. reflexive property 3. ? adc ? ? cba 3. ? 4. ? dac ? ? bca; ? acd ? ? cab 4. cpctc 5. ? dac and ? bca are alt. int. ? s; ? acd and ? cab are alt. int. ? s 5. definition of alternate interior angles 6. ab ? cd; ad ? bc 6. converse of the alternate interior angles theorem 7. abcd is a parallelogram 7. definition of parallelogram what is the missing reason in step 3?