Janet is collecting the results of Herbert Hoover Elementary School's annual standardized test. 340 out of 500 third-graders passed, along with 40 out of 100 fourth graders. The 400 fifth graders had a pass rate that was twice the fourth grades' pass rate. What is the school's overall pass rate?
First find the pass rate for the fourth graders: 40 students / 100 students = 
<gadget id="calculator">40/100</gadget>
<output>2/5 = around 0.4</output>
.4.
Then double that to find the pass rate for the fifth graders: .4 * 2 = 
<gadget id="calculator">.4*2</gadget>
<output>0.8</output>
.8.
Then multiply the fifth graders' pass rate by the number of fifth graders to find the total number of fifth graders who passed: .8 * 400 fifth graders = 
<gadget id="calculator">.8*400</gadget>
<output>320</output>
320 fifth graders.
Now add up the number of passing students from each grade to find to find the total number of passing students: 320 students + 40 students + 340 students = 
<gadget id="calculator">320+40+340</gadget>
<output>700</output>
700 students.
Add up the total number of students in each grade to find the total number of students: 400 students + 100 students + 500 students = 
<gadget id="calculator">400+100+500</gadget>
<output>1_000</output>
1000 students.
Finally, divide the number of passing students by the total number of students and multiply by 100% to find the total number who passed: 700 students / 1000 students * 100% = 70%

<result>70</result>