Evaluate: x/y for x= 3/10 and y= 4/5

a. 7/50
b. 7/15
c. 3/8
d. 12/50

The average human heart beats 1.15 \cdot 10^51.15⋅10 5 1, point, 15, dot, 10, start superscript, 5, end superscript times per day. there are 3.65 \cdot 10^23.65⋅10 2 3, point, 65, dot, 10, start superscript, 2, end superscript days in one year. how many times does the heart beat in one year? write your answer in scientific notation, and round to one decimal place.

What is the answer to this question? i'm a bit stumped. also how do i do it? 5(x - 4) = 2(x + 5)

In right ∆abc shown below, the midpoint of hypotenuse ac is located at d and segment bd is drawn. if ab = 12 and bc = 16, then explain why bd = 10. hint: consider what you know about the diagonals of a rectangle.