diff --git a/lod/01_SPARQL_Introduction.ipynb b/lod/01_SPARQL_Introduction.ipynb
index 0f4e6b8..d8c06cf 100755
--- a/lod/01_SPARQL_Introduction.ipynb
+++ b/lod/01_SPARQL_Introduction.ipynb
@@ -1039,7 +1039,7 @@
     "\n",
     "Once results are grouped, they can be aggregated using any aggregation function, such as `COUNT`.\n",
     "\n",
-    "Using `GROUP BY` and `COUNT`, get the count of songs that use each instrument:"
+    "Using `GROUP BY` and `COUNT`, get the count of songs in which Ringo Starr has played each of the instruments:"
    ]
   },
   {
@@ -1577,7 +1577,7 @@
    "cell_type": "markdown",
    "metadata": {},
    "source": [
-    "### Which songs had Ringo in dums OR Lennon in lead vocals? (UNION)"
+    "### Which songs had Ringo in drums OR Lennon in lead vocals? (UNION)"
    ]
   },
   {
@@ -1643,7 +1643,7 @@
     "editable": false,
     "nbgrader": {
      "cell_type": "code",
-     "checksum": "d583b30a1e00960df3a4411b6854c8c8",
+     "checksum": "11061e79ec06ccb3a9c496319a528366",
      "grade": true,
      "grade_id": "cell-409402df0e801d09",
      "locked": true,
@@ -1654,7 +1654,7 @@
    },
    "outputs": [],
    "source": [
-    "assert len(solution()['tuples']) == 246"
+    "assert len(solution()['tuples']) == 209"
    ]
   },
   {