请出一道类似并不超过中国辽宁省沈阳市审核区七年级下学期北师大的范围---**Question Number:** 6
**Question Stem:**
如图 1, A, C 两地之间有一条笔直的道路, B 地位于 A, C 两地之间. 甲从 B 地出发驾车驶往 C 地, 乙从 A 地出发驾车驶向 C 地. 在行驶过程中, 乙由于汽车故障, 换乘客车 (换乘时间忽略不计) 继续前行, 并与甲同时到达 C 地. 图 2 中线段 MN 和折线 PQN 分别表示甲, 乙两人与 A 地的距离 y (km) 与行驶时间 x (h) 的变化关系, 其中 MN 与 PQ 交于点 E.
**Sub-questions:**
(1) A, B 两地相距 ______ km, 乙比甲晚出发 ______ h;
(2) 求甲, 乙两人的驾车速度;
(3) 求当 x 为何值时, 甲, 乙相距 30 km.
**Fill-in-the-blanks (from Q6.1):**
The blanks are partially filled in the image.
(1) A, B 两地相距 60 km, 乙比甲晚出发 1 h;
**Diagram Description:**
**Figure 1:**
* Type: Line diagram representing a straight road.
* Main Elements:
* Line: A horizontal line segment.
* Points: Points labeled A, B, and C are located on the line segment in that order from left to right.
**Figure 2:**
* Type: Line chart on a coordinate plane.
* Coordinate Axes:
* X-axis: Labeled "x/h", representing time in hours. The origin is O. Marked values are 1, 3, 4, and a.
* Y-axis: Labeled "y/km", representing distance from point A in kilometers. The origin is O. Marked values are 60, 240, 540, and b.
* Data Series/Lines:
* Line segment MN: Represents the relationship between distance from A and time for person 甲 (Jia). It starts at point M and ends at point N. Point M has coordinates (1, 60). Point N has coordinates (a, 540).
* Polyline PQN: Represents the relationship between distance from A and time for person 乙 (Yi). It starts at point P, goes to point Q, and then to point N. Point P is at the origin (0, 0). Point Q appears to have coordinates (4, 540) based on the vertical line to the 540 mark and horizontal line to the 4 mark. Point N is the same endpoint as for MN, (a, 540).
* Points:
* O: Origin (0, 0). Labeled P as well.
* M: (1, 60). Starting point of MN.
* E: Intersection point of MN and PQ. A vertical line from E points to x=3 on the x-axis, and a horizontal line from E points to y=240 on the y-axis. So, E has coordinates (3, 240).
* Q: A point on the polyline PQN. A vertical line from Q points to x=4 on the x-axis, and a horizontal line from Q points to y=540 on the y-axis. So, Q has coordinates (4, 540).
* N: Endpoint of both MN and PQN. A horizontal line from N points to y=540 on the y-axis. A vertical line from N points to x=a on the x-axis. N has coordinates (a, 540).
* Labels and Annotations:
* 'b' is labeled on the y-axis, horizontally aligned with point E. The value of b is 240 based on the position of E.
* 'a' is labeled on the x-axis, vertically aligned with point N.
* Labels O, M, P, Q, E, N for the respective points.
* Figure labels "图 1" and "图 2".