The? half-life of a radioactive substance is 20 years. if you start with some amount of this? substance, what fraction will remain in 120 ? years

answer: 370

step-by-step explanation:

remember use pemdas! there are no parentheses or exponents so lets move onto the first part of the equation: multiplication and division. first, lets break the first part of the equation up into something easier using the distributive property. 28 * 12= (20 *12) + (8*12) you know that 20*12 is 240 and 8*12 is 96. add them and you get 336. then, lets solve the last part of the equation (the last part of pemdas is addition and subtraction). 336 plus 34 is 370. hope this !